diff --git a/README.md b/README.md
index a62d39f..8e23a28 100644
--- a/README.md
+++ b/README.md
@@ -11,334 +11,334 @@ LeetCode is a very good website to sharpen your programming/problem-solving skil
 
 | # | Title | Solution | Difficulty |
 |---| ----- | -------- | ---------- |
-|1|[Two Sum](https://leetcode.com/problems/two-sum/)|[Java,Python](./algorithms/two-sum/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|2|[Add Two Numbers](https://leetcode.com/problems/add-two-numbers/)|[Java,Python](./algorithms/add-two-numbers/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|3|[Longest Substring Without Repeating Characters](https://leetcode.com/problems/longest-substring-without-repeating-characters/)|[Java,Python](./algorithms/longest-substring-without-repeating-characters/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|7|[Reverse Integer](https://leetcode.com/problems/reverse-integer/)|[Java](./algorithms/reverse-integer/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|8|[String to Integer (atoi)](https://leetcode.com/problems/string-to-integer-atoi/)|[Java,Python](./algorithms/string-to-integer/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|9|[Palindrome Number](https://leetcode.com/problems/palindrome-number/)|[Java](./algorithms/palindrome-number/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|11|[Container With Most Water](https://leetcode.com/problems/container-with-most-water/)|[Java,Python](./algorithms/container-with-most-water/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|12|[Integer to Roman](https://leetcode.com/problems/integer-to-roman/)|[Java](./algorithms/integer-to-roman/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|13|[Roman to Integer](https://leetcode.com/problems/roman-to-integer/)|[Java](./algorithms/roman-to-integer/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|14|[Longest Common Prefix](https://leetcode.com/problems/longest-common-prefix/)|[Java](./algorithms/longest-common-prefix/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|15|[3Sum](https://leetcode.com/problems/3sum/)|[Java,Python](./algorithms/3sum/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|16|[3Sum Closest](https://leetcode.com/problems/3sum-closest/)|[Java](./algorithms/3sum-closest/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|17|[Letter Combinations of a Phone Number](https://leetcode.com/problems/letter-combinations-of-a-phone-number/)|[Java](./algorithms/letter-combinations-of-a-phone-number/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|19|[Remove Nth Node From End of List](https://leetcode.com/problems/remove-nth-node-from-end-of-list/)|[Java](./algorithms/remove-nth-node-from-end-of-list/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|20|[Valid Parentheses](https://leetcode.com/problems/valid-parentheses/)|[Java](./algorithms/valid-parentheses/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|21|[Merge Two Sorted Lists](https://leetcode.com/problems/merge-two-sorted-lists/)|[Java,Python](./algorithms/merge-two-sorted-lists/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|22|[Generate Parentheses](https://leetcode.com/problems/generate-parentheses/)|[Java](./algorithms/generate-parentheses/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|23|[Merge k Sorted Lists](https://leetcode.com/problems/merge-k-sorted-lists/)|[Python](./algorithms/merge-k-sorted-lists/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|24|[Swap Nodes in Pairs](https://leetcode.com/problems/swap-nodes-in-pairs/)|[Java](./algorithms/swap-nodes-in-pairs/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|25|[Reverse Nodes in k-Group](https://leetcode.com/problems/reverse-nodes-in-k-group/)|[Python](./algorithms/reverse-nodes-in-k-group/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|26|[Remove Duplicates from Sorted Array](https://leetcode.com/problems/remove-duplicates-from-sorted-array/)|[Java](./algorithms/remove-duplicates-from-sorted-array/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|27|[Remove Element](https://leetcode.com/problems/remove-element/)|[Java](./algorithms/remove-element/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|28|[Implement strStr()](https://leetcode.com/problems/implement-strstr/)|[Java](./algorithms/implement-strstr/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|29|[Divide Two Integers](https://leetcode.com/problems/divide-two-integers/)|[Python](./algorithms/divide-two-integers/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|31|[Next Permutation](https://leetcode.com/problems/next-permutation/)|[Python](./algorithms/next-permutation/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|32|[Longest Valid Parentheses](https://leetcode.com/problems/longest-valid-parentheses/)|[Python](./algorithms/longest-valid-parentheses/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|33|[Search in Rotated Sorted Array](https://leetcode.com/problems/search-in-rotated-sorted-array/)|[Java,Python](./algorithms/search-in-rotated-sorted-array/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|34|[Find First and Last Position of Element in Sorted Array](https://leetcode.com/problems/find-first-and-last-position-of-element-in-sorted-array/)|[Python](./algorithms/find-first-and-last-position-of-element-in-sorted-array/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|35|[Search Insert Position](https://leetcode.com/problems/search-insert-position/)|[Java](./algorithms/search-insert-position/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|36|[Valid Sudoku](https://leetcode.com/problems/valid-sudoku/)|[Java](./algorithms/valid-sudoku/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|38|[Count and Say](https://leetcode.com/problems/count-and-say/)|[Java](./algorithms/count-and-say/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|39|[Combination Sum](https://leetcode.com/problems/combination-sum/)|[Java,Python](./algorithms/combination-sum/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|40|[Combination Sum II](https://leetcode.com/problems/combination-sum-ii/)|[Python](./algorithms/combination-sum-ii/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|41|[First Missing Positive](https://leetcode.com/problems/first-missing-positive/)|[Python](./algorithms/first-missing-positive/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|42|[Trapping Rain Water](https://leetcode.com/problems/trapping-rain-water/)|[Python](./algorithms/trapping-rain-water/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|43|[Multiply Strings](https://leetcode.com/problems/multiply-strings/)|[Java](./algorithms/multiply-strings/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|46|[Permutations](https://leetcode.com/problems/permutations/)|[Java,Python](./algorithms/permutations/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|47|[Permutations II](https://leetcode.com/problems/permutations-ii/)|[Python](./algorithms/permutations-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|48|[Rotate Image](https://leetcode.com/problems/rotate-image/)|[Python](./algorithms/rotate-image/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|49|[Group Anagrams](https://leetcode.com/problems/group-anagrams/)|[Python](./algorithms/group-anagrams/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|50|[Pow(x, n)](https://leetcode.com/problems/powx-n/)|[Java](./algorithms/pow(x,n)/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|53|[Maximum Subarray](https://leetcode.com/problems/maximum-subarray/)|[Java,Python](./algorithms/maximum-subarray/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|54|[Spiral Matrix](https://leetcode.com/problems/spiral-matrix/)|[Java,Python](./algorithms/spiral-matrix/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|55|[Jump Game](https://leetcode.com/problems/jump-game/)|[Java](./algorithms/jump-game/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|56|[Merge Intervals](https://leetcode.com/problems/merge-intervals/)|[Python](./algorithms/merge-intervals/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|56|[Insert Interval](https://leetcode.com/problems/insert-interval/)|[Python](./algorithms/insert-interval/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|58|[Length of Last Word](https://leetcode.com/problems/length-of-last-word/)|[Java](./algorithms/length-of-last-word/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|59|[Spiral Matrix II](https://leetcode.com/problems/spiral-matrix-ii/)|[Python](./algorithms/spiral-matrix-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|60|[Permutation Sequence](https://leetcode.com/problems/permutation-sequence/)|[Python](./algorithms/permutation-sequence/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|61|[Rotate List](https://leetcode.com/problems/rotate-list/)|[Java,Python](./algorithms/rotate-list/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|62|[Unique Paths](https://leetcode.com/problems/unique-paths/)|[Python](./algorithms/unique-paths/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|63|[Unique Paths II](https://leetcode.com/problems/unique-paths-ii/)|[Python](./algorithms/unique-paths-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|64|[Minimum Path Sum](https://leetcode.com/problems/minimum-path-sum/)|[Python](./algorithms/minimum-path-sum/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|66|[Plus One](https://leetcode.com/problems/plus-one/)|[Java](./algorithms/plus-one/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|67|[Add Binary](https://leetcode.com/problems/add-binary/)|[Java](./algorithms/add-binary/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|69|[Sqrt(x)](https://leetcode.com/problems/sqrtx/)|[C++,Python](./algorithms/sqrtx/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|70|[Climbing Stairs](https://leetcode.com/problems/climbing-stairs/)|[Java](./algorithms/climbing-stairs/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|71|[Simplify Path](https://leetcode.com/problems/simplify-path/)|[Python](./algorithms/simplify-path/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|72|[Edit Distance](https://leetcode.com/problems/edit-distance/)|[Java,C++](./algorithms/edit-distance/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|73|[Set Matrix Zeroes](https://leetcode.com/problems/set-matrix-zeroes/)|[Java](./algorithms/set-matrix-zeroes/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|74|[Search a 2D Matrix](https://leetcode.com/problems/search-a-2d-matrix/)|[Java](./algorithms/search-a-2d-matrix/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|75|[Sort Colors](https://leetcode.com/problems/sort-colors/)|[Java,Python](./algorithms/sort-colors/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|76|[Minimum Window Substring](https://leetcode.com/problems/minimum-window-substring/)|[Python](./algorithms/minimum-window-substring/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|77|[Combinations](https://leetcode.com/problems/combinations/)|[Java,Python](./algorithms/combinations/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|78|[Subsets](https://leetcode.com/problems/subsets/)|[Python](./algorithms/subsets/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|79|[Word Search](https://leetcode.com/problems/word-search/)|[Python](./algorithms/word-search/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|80|[Remove Duplicates from Sorted Array II](https://leetcode.com/problems/remove-duplicates-from-sorted-array-ii/)|[Java](./algorithms/remove-duplicates-from-sorted-array-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|81|[Search in Rotated Sorted Array II](https://leetcode.com/problems/search-in-rotated-sorted-array-ii/)|[Python](./algorithms/search-in-rotated-sorted-array-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|82|[Remove Duplicates from Sorted List II](https://leetcode.com/problems/remove-duplicates-from-sorted-list-ii/)|[C++,Java,Python](./algorithms/remove-duplicates-from-sorted-list-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|83|[Remove Duplicates from Sorted List](https://leetcode.com/problems/remove-duplicates-from-sorted-list/)|[Java](./algorithms/remove-duplicates-from-sorted-list/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|84|[Largest Rectangle in Histogram](https://leetcode.com/problems/largest-rectangle-in-histogram/)|[Python](./algorithms/largest-rectangle-in-histogram/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|85|[Maximal Rectangle](https://leetcode.com/problems/maximal-rectangle/)|[Python](./algorithms/maximal-rectangle/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|86|[Partition List](https://leetcode.com/problems/partition-list/)|[Python](./algorithms/partition-list/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|88|[Merge Sorted Array](https://leetcode.com/problems/merge-sorted-array/)|[Java](./algorithms/merge-sorted-array/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|92|[Reverse Linked List II](https://leetcode.com/problems/reverse-linked-list-ii/)|[Java](./algorithms/reverse-linked-list-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|98|[Validate Binary Search Tree](https://leetcode.com/problems/validate-binary-search-tree/)|[Java](./algorithms/validate-binary-search-tree/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|100|[Same Tree](https://leetcode.com/problems/same-tree/)|[Java](./algorithms/same-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|101|[Symmetric Tree](https://leetcode.com/problems/symmetric-tree/)|[Java](./algorithms/symmetric-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|102|[Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/)|[Java,Python](./algorithms/binary-tree-level-order-traversal/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|103|[Binary Tree Zigzag Level Order Traversal](https://leetcode.com/problems/binary-tree-zigzag-level-order-traversal/)|[Python](./algorithms/binary-tree-zigzag-level-order-traversal/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|104|[Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree/)|[Java,Python](./algorithms/maximum-depth-of-binary-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|105|[Construct Binary Tree from Preorder and Inorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/)|[Python](./algorithms/construct-binary-tree-from-preorder-and-inorder-traversal/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|106|[Construct Binary Tree from Inorder and Postorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal/)|[Python](./algorithms/construct-binary-tree-from-inorder-and-postorder-traversal/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|107|[Binary Tree Level Order Traversal II](https://leetcode.com/problems/binary-tree-level-order-traversal-ii/)|[Java](./algorithms/binary-tree-level-order-traversal-ii/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|108|[Convert Sorted Array to Binary Search Tree](https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/)|[Python](./algorithms/convert-sorted-array-to-binary-search-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|109|[Convert Sorted List to Binary Search Tree](https://leetcode.com/problems/convert-sorted-list-to-binary-search-tree)|[Python](./algorithms/convert-sorted-list-to-binary-search-tree/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|110|[Balanced Binary Tree](https://leetcode.com/problems/balanced-binary-tree/)|[Java](./algorithms/balanced-binary-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|111|[Minimum Depth of Binary Tree](https://leetcode.com/problems/minimum-depth-of-binary-tree/)|[Java](./algorithms/minimum-depth-of-binary-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|112|[Path Sum](https://leetcode.com/problems/path-sum/)|[Java,Python](./algorithms/path-sum/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|113|[Path Sum II](https://leetcode.com/problems/path-sum-ii/)|[Java,Python](./algorithms/path-sum-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|118|[Pascal's Triangle](https://leetcode.com/problems/pascals-triangle/)|[Java](./algorithms/pascals-triangle/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|119|[Pascal's Triangle II](https://leetcode.com/problems/pascals-triangle-ii/)|[Java](./algorithms/pascals-triangle-ii/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|121|[Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/)|[Python](./algorithms/best-time-to-buy-and-sell-stock/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|125|[Valid Palindrome](https://leetcode.com/problems/valid-palindrome/)|[Java](./algorithms/valid-palindrome/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|127|[Word Ladder](https://leetcode.com/problems/word-ladder/)|[Python,Java](./algorithms/word-ladder/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|129|[Sum Root to Leaf Numbers](https://leetcode.com/problems/sum-root-to-leaf-numbers/)|[Java](./algorithms/sum-root-to-leaf-numbers/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|131|[Palindrome Partitioning](https://leetcode.com/problems/palindrome-partitioning/)|[Python](./algorithms/palindrome-partitioning/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|134|[Gas Station](https://leetcode.com/problems/gas-station/)|[Python](./algorithms/gas-station/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|135|[Candy](https://leetcode.com/problems/candy/)|[Python](./algorithms/candy/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|136|[Single Number](https://leetcode.com/problems/single-number/)|[Java](./algorithms/single-number/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|137|[Single Number II](https://leetcode.com/problems/single-number-ii/)|[Java](./algorithms/single-number-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|138|[Copy List with Random Pointer](https://leetcode.com/problems/copy-list-with-random-pointer/)|[Java](./algorithms/copy-list-with-random-pointer/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|139|[Word Break](https://leetcode.com/problems/word-break/)|[Java](./algorithms/word-break/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|141|[Linked List Cycle](https://leetcode.com/problems/linked-list-cycle/)|[Java](./algorithms/linked-list-cycle/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|142|[Linked List Cycle II](https://leetcode.com/problems/linked-list-cycle-ii/)|[Java](./algorithms/linked-list-cycle-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|144|[Binary Tree Preorder Traversal](https://leetcode.com/problems/binary-tree-preorder-traversal/)|[Python](./algorithms/binary-tree-preorder-traversal/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|145|[Binary Tree Postorder Traversal](https://leetcode.com/problems/binary-tree-postorder-traversal/)|[Python](./algorithms/binary-tree-postorder-traversal/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|146|[LRU Cache](https://leetcode.com/problems/lru-cache/)|[Python](./algorithms/lru-cache/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|147|[Insertion Sort List](https://leetcode.com/problems/insertion-sort-list/)|[Python](./algorithms/insertion-sort-list/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|148|[Sort List](https://leetcode.com/problems/sort-list/)|[Python](./algorithms/sort-list/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|149|[Max Points on a Line](https://leetcode.com/problems/max-points-on-a-line/)|[Java](./algorithms/max-points-on-a-line/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|150|[Evaluate Reverse Polish Notation](https://leetcode.com/problems/evaluate-reverse-polish-notation/)|[Python](./algorithms/evaluate-reverse-polish-notation/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|151|[Reverse Words in a String](https://leetcode.com/problems/reverse-words-in-a-string/)|[Python](./algorithms/reverse-words-in-a-string/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|152|[Maximum Product Subarray](https://leetcode.com/problems/maximum-product-subarray/)|[Python](./algorithms/maximum-product-subarray/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|153|[Find Minimum in Rotated Sorted Array](https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/)|[Python](./algorithms/find-minimum-in-rotated-sorted-array/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|155|[Min Stack](https://leetcode.com/problems/min-stack/)|[Java,Python](./algorithms/min-stack/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|160|[Intersection of Two Linked Lists](https://leetcode.com/problems/intersection-of-two-linked-lists/)|[Java,Python](./algorithms/intersection-of-two-linked-lists/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|162|[Find Peak Element](https://leetcode.com/problems/find-peak-element/)|[Java,Python](./algorithms/find-peak-element/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|165|[Compare Version Numbers](https://leetcode.com/problems/compare-version-numbers/)|[Java,Python](./algorithms/compare-version-numbers/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|166|[Fraction to Recurring Decimal](https://leetcode.com/problems/fraction-to-recurring-decimal/)|[Python](./algorithms/fraction-to-recurring-decimal/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|167|[Two Sum II - Input array is sorted](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/)|[Python](./algorithms/two-sum-ii-input-array-is-sorted/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|168|[Excel Sheet Column Title](https://leetcode.com/problems/excel-sheet-column-title/)|[Python](./algorithms/excel-sheet-column-title/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|169|[Majority Element](https://leetcode.com/problems/majority-element/)|[Java,Python](./algorithms/majority-element/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|171|[Excel Sheet Column Number](https://leetcode.com/problems/excel-sheet-column-number/)|[Python](./algorithms/excel-sheet-column-number/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|172|[Factorial Trailing Zeroes](https://leetcode.com/problems/factorial-trailing-zeroes/)|[Python](./algorithms/factorial-trailing-zeroes/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|173|[Binary Search Tree Iterator](https://leetcode.com/problems/binary-search-tree-iterator/)|[Python](./algorithms/binary-search-tree-iterator/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|175|[Combine Two Tables](https://leetcode.com/problems/combine-two-tables/)|[SQL](./databases/combine-two-tables/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|176|[Second Highest Salary](https://leetcode.com/problems/second-highest-salary/)|[SQL](./databases/second-highest-salary/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|177|[Nth Highest Salary](https://leetcode.com/problems/nth-highest-salary/)|[SQL](./databases/nth-highest-salary/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|178|[Rank Scores](https://leetcode.com/problems/rank-scores/)|[SQL](./databases/rank-scores/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|179|[Largest Number](https://leetcode.com/problems/largest-number/)|[Python](./algorithms/largest-number/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|180|[Consecutive Numbers](https://leetcode.com/problems/consecutive-numbers/)|[SQL](./databases/consecutive-numbers/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|181|[Employees Earning More Than Their Managers](https://leetcode.com/problems/employees-earning-more-than-their-managers/)|[SQL](./databases/employees-earning-more-than-their-managers/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|182|[Duplicate Emails](https://leetcode.com/problems/duplicate-emails/)|[SQL](./databases/duplicate-emails/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|183|[Customers Who Never Order](https://leetcode.com/problems/customers-who-never-order/)|[SQL](./databases/customers-who-never-order/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|184|[Department Highest Salary](https://leetcode.com/problems/department-highest-salary/)|[SQL](./databases/department-highest-salary/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|185|[Department Top Three Salaries](https://leetcode.com/problems/department-top-three-salaries/)|[SQL](./databases/department-top-three-salaries/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|187|[Repeated DNA Sequences](https://leetcode.com/problems/repeated-dna-sequences/)|[Java,Python](./algorithms/repeated-dna-sequences/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|188|[Best Time to Buy and Sell Stock IV](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-iv/)|[Python](./algorithms/best-time-to-buy-and-sell-stock-iv/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|189|[Rotate Array](https://leetcode.com/problems/rotate-array/)|[Java,Python](./algorithms/rotate-array/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|190|[Reverse Bits](https://leetcode.com/problems/reverse-bits/)|[Java,Python](./algorithms/reverse-bits/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|191|[Number of 1 Bits](https://leetcode.com/problems/number-of-1-bits/)|[Java,Python](./algorithms/number-of-1-bits/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|192|[Word Frequency](https://leetcode.com/problems/word-frequency/)|[Shell](./shell/word-frequency/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|193|[Valid Phone Numbers](https://leetcode.com/problems/valid-phone-numbers/)|[Shell](./shell/valid-phone-numbers/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|194|[Transpose File](https://leetcode.com/problems/transpose-file/)|[Shell](./shell/transpose-file/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|195|[Tenth Line](https://leetcode.com/problems/tenth-line/)|[Shell](./shell/tenth-line/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|196|[Delete Duplicate Emails](https://leetcode.com/problems/delete-duplicate-emails/)|[SQL](./databases/delete-duplicate-emails/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|197|[Rising Temperature](https://leetcode.com/problems/rising-temperature/)|[SQL](./databases/rising-temperature/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|198|[House Robber](https://leetcode.com/problems/house-robber/)|[Java,Python](./algorithms/house-robber/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|199|[Binary Tree Right Side View](https://leetcode.com/problems/binary-tree-right-side-view/)|[Python](./algorithms/binary-tree-right-side-view/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|200|[Number of Islands](https://leetcode.com/problems/number-of-islands)|[Python](./algorithms/number-of-islands/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|201|[Bitwise AND of Numbers Range](https://leetcode.com/problems/bitwise-and-of-numbers-range)|[Python](./algorithms/bitwise-and-of-numbers-range/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|202|[Happy Number](https://leetcode.com/problems/happy-number/)|[Java](./algorithms/happy-number/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|203|[Remove Linked List Elements](https://leetcode.com/problems/remove-linked-list-elements/)|[Java,Python](./algorithms/remove-linked-list-elements/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|204|[Count Primes](https://leetcode.com/problems/count-primes/)|[Python](./algorithms/count-primes/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|205|[Isomorphic Strings](https://leetcode.com/problems/isomorphic-strings/)|[Java,Python](./algorithms/isomorphic-strings/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|206|[Reverse Linked List](https://leetcode.com/problems/reverse-linked-list/)|[Java,Python](./algorithms/reverse-linked-list/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|207|[Course Schedule](https://leetcode.com/problems/course-schedule/)|[Python](./algorithms/course-schedule/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|208|[Implement Trie (Prefix Tree)](https://leetcode.com/problems/implement-trie-prefix-tree/)|[Python](./algorithms/implement-trie-prefix-tree/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|209|[Minimum Size Subarray Sum](https://leetcode.com/problems/minimum-size-subarray-sum/)|[Python](./algorithms/minimum-size-subarray-sum/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|210|[Course Schedule II](https://leetcode.com/problems/course-schedule-ii/)|[Python](./algorithms/course-schedule-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|211|[Add and Search Word - Data structure design](https://leetcode.com/problems/add-and-search-word-data-structure-design/)|[Python](./algorithms/add-and-search-word-data-structure-design/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|212|[Word Search II](https://leetcode.com/problems/word-search-ii/)|[Python](./algorithms/word-search-ii/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|213|[House Robber II](https://leetcode.com/problems/house-robber-ii/)|[Python](./algorithms/house-robber-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|215|[Kth Largest Element in an Array](https://leetcode.com/problems/kth-largest-element-in-an-array/)|[Python](./algorithms/kth-largest-element-in-an-array/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|216|[Combination Sum III](https://leetcode.com/problems/combination-sum-iii/)|[Python](./algorithms/combination-sum-iii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|217|[Contains Duplicate](https://leetcode.com/problems/contains-duplicate/)|[Java,Python](./algorithms/contains-duplicate/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|218|[The Skyline Problem](https://leetcode.com/problems/the-skyline-problem/)|[Python](./algorithms/the-skyline-problem/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|219|[Contains Duplicate II](https://leetcode.com/problems/contains-duplicate-ii/)|[Java,Python](./algorithms/contains-duplicate-ii/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|220|[Contains Duplicate III](https://leetcode.com/problems/contains-duplicate-iii/)|[Python](./algorithms/contains-duplicate-iii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|221|[Maximal Square](https://leetcode.com/problems/maximal-square/)|[Python](./algorithms/maximal-square/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|222|[Count Complete Tree Nodes](https://leetcode.com/problems/count-complete-tree-nodes/)|[Python](./algorithms/count-complete-tree-nodes/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|226|[Implement Stack using Queues](https://leetcode.com/problems/implement-stack-using-queues/)|[Python](./algorithms/implement-stack-using-queues/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|227|[Basic Calculator II](https://leetcode.com/problems/basic-calculator-ii/)|[Python](./algorithms/basic-calculator-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|228|[Summary Ranges](https://leetcode.com/problems/summary-ranges/)|[Java,Python](./algorithms/summary-ranges/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|229|[Majority Element II](https://leetcode.com/problems/majority-element-ii/)|[Java,Python](./algorithms/majority-element-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|230|[Kth Smallest Element in a BST](https://leetcode.com/problems/kth-smallest-element-in-a-bst/)|[Python](./algorithms/kth-smallest-element-in-a-bst/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|231|[Power of Two](https://leetcode.com/problems/power-of-two/)|[Python](./algorithms/power-of-two/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|232|[Implement Queue using Stacks](https://leetcode.com/problems/implement-queue-using-stacks/)|[Python](./algorithms/implement-queue-using-stacks/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|233|[Number of Digit One](https://leetcode.com/problems/number-of-digit-one/)|[C++,Python](./algorithms/number-of-digit-one/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|234|[Palindrome Linked List](https://leetcode.com/problems/palindrome-linked-list/)|[Java,Python](./algorithms/palindrome-linked-list/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|235|[Lowest Common Ancestor of a Binary Search Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/)|[Java,Python](./algorithms/lowest-common-ancestor-of-a-binary-search-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|236|[Lowest Common Ancestor of a Binary Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/)|[Python](./algorithms/lowest-common-ancestor-of-a-binary-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|237|[Delete Node in a Linked List](https://leetcode.com/problems/delete-node-in-a-linked-list/)|[C++,Python](./algorithms/delete-node-in-a-linked-list/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|238|[Product of Array Except Self](https://leetcode.com/problems/product-of-array-except-self/)|[Python](./algorithms/product-of-array-except-self/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|242|[Valid Anagram](https://leetcode.com/problems/valid-anagram/)|[Java](./algorithms/valid-anagram/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|257|[Binary Tree Paths](https://leetcode.com/problems/binary-tree-paths/)|[Java](./algorithms/binary-tree-paths/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|258|[Add Digits](https://leetcode.com/problems/add-digits/)|[C++](./algorithms/add-digits/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|260|[Single Number III](https://leetcode.com/problems/single-number-iii/)|[Java](./algorithms/single-number-iii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|262|[Trips and Users](https://leetcode.com/problems/trips-and-users/)|[SQL](./databases/trips-and-users/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|263|[Ugly Number](https://leetcode.com/problems/ugly-number/)|[Java](./algorithms/ugly-number/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|264|[Ugly Number II](https://leetcode.com/problems/ugly-number-ii/)|[Java](./algorithms/ugly-number-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|268|[Missing Number](https://leetcode.com/problems/missing-number/)|[Java](./algorithms/missing-number/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|273|[Integer to English Words](https://leetcode.com/problems/integer-to-english-words/)|[Java](./algorithms/integer-to-english-words/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|274|[H-Index](https://leetcode.com/problems/h-index/)|[Java](./algorithms/h-index/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|275|[H-Index II](https://leetcode.com/problems/h-index-ii/)|[Java](./algorithms/h-index-2/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|279|[Perfect Squares](https://leetcode.com/problems/perfect-squares/)|[Java](./algorithms/perfect-squares/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|283|[Move Zeroes](https://leetcode.com/problems/move-zeroes/)|[C++](./algorithms/move-zeroes/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|284|[Peeking Iterator](https://leetcode.com/problems/peeking-iterator/)|[Java](./algorithms/peeking-iterator/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|287|[Find the Duplicate Number](https://leetcode.com/problems/find-the-duplicate-number/)|[Java,Python](./algorithms/find-the-duplicate-number/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|290|[Word Pattern](https://leetcode.com/problems/word-pattern/)|[Java](./algorithms/word-pattern/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|292|[Nim Game](https://leetcode.com/problems/nim-game/)|[C++](./algorithms/nim-game/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|295|[Find Median from Data Stream](https://leetcode.com/problems/find-median-from-data-stream/)|[Java](./algorithms/find-median-from-data-stream/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|299|[Bulls and Cows](https://leetcode.com/problems/bulls-and-cows/)|[Java](./algorithms/bulls-and-cows/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|300|[Longest Increasing Subsequence](https://leetcode.com/problems/longest-increasing-subsequence/)|[Java](./algorithms/longest-increasing-subsequence/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|303|[Range Sum Query - Immutable](https://leetcode.com/problems/range-sum-query-immutable/)|[Java](./algorithms/range-sum-query-immutable/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|304|[Range Sum Query 2D - Immutable](https://leetcode.com/problems/range-sum-query-2d-immutable/)|[Java](./algorithms/range-sum-query-2d-immutable/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|316|[Remove Duplicate Letters](https://leetcode.com/problems/remove-duplicate-letters/)|[Python](./algorithms/remove-duplicate-letters/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|317|[Shortest Distance from All Buildings](https://leetcode.com/problems/shortest-distance-from-all-buildings/)|[Python](./algorithms/shortest-distance-from-all-buildings/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|328|[Odd Even Linked List](https://leetcode.com/problems/odd-even-linked-list/)|[Java](./algorithms/odd-even-linked-list/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|330|[Patching Array](https://leetcode.com/problems/patching-array/)|[Java](./algorithms/patching-array/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|338|[Counting Bits](https://leetcode.com/problems/counting-bits/)|[Java](./algorithms/counting-bits/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|344|[Reverse String](https://leetcode.com/problems/reverse-string/)|[Java](./algorithms/reverse-string/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|367|[Valid Perfect Square](https://leetcode.com/problems/valid-perfect-square/)|[C++](./algorithms/valid-perfect-square/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|371|[Sum of Two Integers](https://leetcode.com/problems/sum-of-two-integers/)|[Java](./algorithms/sum-of-two-integers/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|389|[Find the Difference](https://leetcode.com/problems/find-the-difference/)|[Python](./algorithms/find-the-difference/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|392|[Is Subsequence](https://leetcode.com/problems/is-subsequence/)|[Java,Python](./algorithms/is-subsequence/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|394|[Decode String](https://leetcode.com/problems/decode-string/)|[Python](./algorithms/decode-string/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|437|[Path Sum III](https://leetcode.com/problems/path-sum-iii/)|[Java](./algorithms/path-sum-iii/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|438|[Find All Anagrams in a String](https://leetcode.com/problems/find-all-anagrams-in-a-string/)|[Java](./algorithms/find-all-anagrams-in-a-string/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|445|[Add Two Numbers II](https://leetcode.com/problems/add-two-numbers-ii/)|[Python](./algorithms/add-two-numbers-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|448|[Find All Numbers Disappeared in an Array](https://leetcode.com/problems/find-all-numbers-disappeared-in-an-array/)|[Java](./algorithms/find-all-numbers-disappeared-in-an-array/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|449|[Serialize and Deserialize BST](https://leetcode.com/problems/serialize-and-deserialize-bst/)|[Python](./algorithms/serialize-and-deserialize-bst/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|452|[Minimum Number of Arrows to Burst Balloons](https://leetcode.com/problems/minimum-number-of-arrows-to-burst-balloons/)|[Python](./algorithms/minimum-number-of-arrows-to-burst-balloons/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|461|[Hamming Distance](https://leetcode.com/problems/hamming-distance/)|[Java](./algorithms/hamming-distance/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|485|[Max Consecutive Ones](https://leetcode.com/problems/max-consecutive-ones/)|[Java](./algorithms/max-consecutive-ones/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|496|[Next Greater Element I](https://leetcode.com/problems/next-greater-element-i/)|[Python](./algorithms/next-greater-element-i/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|500|[Keyboard Row](https://leetcode.com/problems/keyboard-row/)|[Python](./algorithms/keyboard-row/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|503|[Next Greater Element II](https://leetcode.com/problems/next-greater-element-ii/)|[Java](./algorithms/next-greater-element-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|532|[K-diff Pairs in an Array](https://leetcode.com/problems/k-diff-pairs-in-an-array/)|[Python](./algorithms/k-diff-pairs-in-an-array/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|538|[Convert BST to Greater Tree](https://leetcode.com/problems/convert-bst-to-greater-tree/)|[Java](./algorithms/convert-bst-to-greater-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|543|[Diameter of Binary Tree](https://leetcode.com/problems/diameter-of-binary-tree/)|[Java,Python](./algorithms/diameter-of-binary-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|560|[Subarray Sum Equals K](https://leetcode.com/problems/subarray-sum-equals-k/)|[Java](./algorithms/subarray-sum-equals-k/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|561|[Array Partition I](https://leetcode.com/problems/array-partition-i/)|[Python](./algorithms/array-partition-i/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|572|[Subtree of Another Tree](https://leetcode.com/problems/subtree-of-another-tree/)|[Java](./algorithms/subtree-of-another-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|581|[Shortest Unsorted Continuous Subarray](https://leetcode.com/problems/shortest-unsorted-continuous-subarray/)|[Java](./algorithms/shortest-unsorted-continuous-subarray/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|595|[Big Countries](https://leetcode.com/problems/big-countries/)|[SQL](./databases/big-countries/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|596|[Classes More Than 5 Students](https://leetcode.com/problems/classes-more-than-5-students/)|[SQL](./databases/classes-more-than-5-students/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|601|[Human Traffic of Stadium](https://leetcode.com/problems/human-traffic-of-stadium/)|[SQL](./databases/human-traffic-of-stadium/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|605|[Can Place Flowers](https://leetcode.com/problems/can-place-flowers/)|[Java](./algorithms/can-place-flowers/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|617|[Merge Two Binary Trees](https://leetcode.com/problems/merge-two-binary-trees/)|[Java](./algorithms/merge-two-binary-trees/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|620|[Not Boring Movies](https://leetcode.com/problems/not-boring-movies/)|[SQL](./databases/not-boring-movies/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|626|[Exchange Seats](https://leetcode.com/problems/exchange-seats/)|[SQL](./databases/exchange-seats/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|627|[Swap Salary](https://leetcode.com/problems/swap-salary/)|[SQL](./databases/swap-salary/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|643|[Maximum Average Subarray I](https://leetcode.com/problems/maximum-average-subarray-i/)|[Python](./algorithms/maximum-average-subarray-i/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|645|[Set Mismatch](https://leetcode.com/problems/set-mismatch/)|[Python](./algorithms/set-mismatch/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|653|[Two Sum IV - Input is a BST](https://leetcode.com/problems/two-sum-iv-input-is-a-bst/)|[Python](./algorithms/two-sum-iv-input-is-a-bst/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|657|[Judge Route Circle](https://leetcode.com/problems/judge-route-circle/)|[Python](./algorithms/judge-route-circle/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|661|[Image Smoother](https://leetcode.com/problems/image-smoother/)|[Python](./algorithms/image-smoother/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|665|[Non-decreasing Array](https://leetcode.com/problems/non-decreasing-array/)|[Python](./algorithms/non-decreasing-array/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|669|[Trim a Binary Search Tree](https://leetcode.com/problems/trim-a-binary-search-tree/)|[Python](./algorithms/trim-a-binary-search-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|670|[Maximum Swap](https://leetcode.com/problems/maximum-swap/)|[Python](./algorithms/maximum-swap/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|671|[Second Minimum Node In a Binary Tree](https://leetcode.com/problems/second-minimum-node-in-a-binary-tree/)|[Python](./algorithms/second-minimum-node-in-a-binary-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|674|[Longest Continuous Increasing Subsequence](https://leetcode.com/problems/longest-continuous-increasing-subsequence/)|[Python](./algorithms/longest-continuous-increasing-subsequence/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|680|[Valid Palindrome II](https://leetcode.com/problems/valid-palindrome-ii/)|[Python](./algorithms/valid-palindrome-ii/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|682|[Baseball Game](https://leetcode.com/problems/baseball-game/)|[Python](./algorithms/baseball-game/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|686|[Repeated String Match](https://leetcode.com/problems/repeated-string-match/)|[Python](./algorithms/repeated-string-match/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|687|[Longest Univalue Path](https://leetcode.com/problems/longest-univalue-path/)|[Python](./algorithms/longest-univalue-path/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|690|[Employee Importance](https://leetcode.com/problems/employee-importance/)|[Python](./algorithms/employee-importance/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|693|[Binary Number with Alternating Bits](https://leetcode.com/problems/binary-number-with-alternating-bits/)|[Python](./algorithms/binary-number-with-alternating-bits/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|695|[Max Area of Island](https://leetcode.com/problems/max-area-of-island/)|[Python](./algorithms/max-area-of-island/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|696|[Count Binary Substrings](https://leetcode.com/problems/count-binary-substrings/)|[Python](./algorithms/count-binary-substrings/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|697|[Degree of an Array](https://leetcode.com/problems/degree-of-an-array/)|[Python](./algorithms/degree-of-an-array/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|700|[Search in a Binary Search Tree](https://leetcode.com/problems/search-in-a-binary-search-tree/)|[Python](./algorithms/search-in-a-binary-search-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|701|[Insert into a Binary Search Tree](https://leetcode.com/problems/insert-into-a-binary-search-tree/)|[Python](./algorithms/insert-into-a-binary-search-tree/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|704|[Binary Search](https://leetcode.com/problems/binary-search/)|[Python](./algorithms/binary-search/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|705|[Design HashSet](https://leetcode.com/problems/design-hashset/)|[Python](./algorithms/design-hashset/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|706|[Design HashMap](https://leetcode.com/problems/design-hashmap/)|[Python](./algorithms/design-hashmap/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|707|[Design Linked List](https://leetcode.com/problems/design-linked-list/)|[Python](./algorithms/design-linked-list/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|709|[To Lower Case](https://leetcode.com/problems/to-lower-case/)|[Python](./algorithms/to-lower-case/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|717|[1-bit and 2-bit Characters](https://leetcode.com/problems/1-bit-and-2-bit-characters/)|[Python](./algorithms/1-bit-and-2-bit-characters/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|720|[Longest Word in Dictionary](https://leetcode.com/problems/longest-word-in-dictionary/)|[Python](./algorithms/longest-word-in-dictionary/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|724|[Find Pivot Index](https://leetcode.com/problems/find-pivot-index/)|[Python](./algorithms/find-pivot-index/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|728|[Self Dividing Numbers](https://leetcode.com/problems/self-dividing-numbers/)|[Python](./algorithms/self-dividing-numbers/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|733|[Flood Fill](https://leetcode.com/problems/flood-fill/)|[Python](./algorithms/flood-fill/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|744|[Find Smallest Letter Greater Than Target](https://leetcode.com/problems/find-smallest-letter-greater-than-target/)|[Python](./algorithms/find-smallest-letter-greater-than-target/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|746|[Min Cost Climbing Stairs](https://leetcode.com/problems/min-cost-climbing-stairs/)|[Python](./algorithms/min-cost-climbing-stairs/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|747|[Largest Number At Least Twice of Others](https://leetcode.com/problems/largest-number-at-least-twice-of-others/)|[Python](./algorithms/largest-number-at-least-twice-of-others/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|762|[Prime Number of Set Bits in Binary Representation](https://leetcode.com/problems/prime-number-of-set-bits-in-binary-representation/)|[Python](./algorithms/prime-number-of-set-bits-in-binary-representation/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|766|[Toeplitz Matrix](https://leetcode.com/problems/toeplitz-matrix/)|[Python](./algorithms/toeplitz-matrix/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|771|[Jewels and Stones](https://leetcode.com/problems/jewels-and-stones/)|[Python](./algorithms/jewels-and-stones/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|784|[Letter Case Permutation](https://leetcode.com/problems/letter-case-permutation/)|[Python](./algorithms/letter-case-permutation/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|788|[Rotated Digits](https://leetcode.com/problems/rotated-digits/)|[Python](./algorithms/rotated-digits/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|796|[Rotate String](https://leetcode.com/problems/rotate-string/)|[Python](./algorithms/rotate-string/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|804|[Unique Morse Code Words](https://leetcode.com/problems/unique-morse-code-words/)|[Python](./algorithms/unique-morse-code-words/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|806|[Number of Lines To Write String](https://leetcode.com/problems/number-of-lines-to-write-string/)|[Python](./algorithms/number-of-lines-to-write-string/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|811|[Subdomain Visit Count](https://leetcode.com/problems/subdomain-visit-count/)|[Python](./algorithms/subdomain-visit-count/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|812|[Largest Triangle Area](https://leetcode.com/problems/largest-triangle-area/)|[Python](./algorithms/largest-triangle-area/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|819|[Most Common Word](https://leetcode.com/problems/most-common-word/)|[Python](./algorithms/most-common-word/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|821|[Shortest Distance to a Character](https://leetcode.com/problems/shortest-distance-to-a-character/)|[Python](./algorithms/shortest-distance-to-a-character/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|824|[Goat Latin](https://leetcode.com/problems/goat-latin/)|[Python](./algorithms/goat-latin/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|830|[Positions of Large Groups](https://leetcode.com/problems/positions-of-large-groups/)|[Python](./algorithms/positions-of-large-groups/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|832|[Flipping an Image](https://leetcode.com/problems/flipping-an-image/)|[Java](./algorithms/flipping-an-image/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|836|[Rectangle Overlap](https://leetcode.com/problems/rectangle-overlap/)|[Python](./algorithms/rectangle-overlap/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|840|[Magic Squares In Grid](https://leetcode.com/problems/magic-squares-in-grid/)|[Python](./algorithms/magic-squares-in-grid/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|844|[Backspace String Compare](https://leetcode.com/problems/backspace-string-compare/)|[Python](./algorithms/backspace-string-compare/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|849|[Maximize Distance to Closest Person](https://leetcode.com/problems/maximize-distance-to-closest-person/)|[Python](./algorithms/maximize-distance-to-closest-person/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|852|[Peak Index in a Mountain Array](https://leetcode.com/problems/peak-index-in-a-mountain-array/)|[Python](./algorithms/peak-index-in-a-mountain-array/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|859|[Buddy Strings](https://leetcode.com/problems/buddy-strings/)|[Python](./algorithms/buddy-strings/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|860|[Lemonade Change](https://leetcode.com/problems/lemonade-change/)|[Python](./algorithms/lemonade-change/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|867|[Binary Gap](https://leetcode.com/problems/binary-gap/)|[Python](./algorithms/binary-gap/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|868|[Transpose Matrix](https://leetcode.com/problems/transpose-matrix/)|[Python](./algorithms/transpose-matrix/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|872|[Leaf-Similar Trees](https://leetcode.com/problems/leaf-similar-trees/)|[Java](./algorithms/leaf-similar-trees/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|874|[Walking Robot Simulation](https://leetcode.com/problems/walking-robot-simulation/)|[Java](./algorithms/walking-robot-simulation/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|876|[Middle of the Linked List](https://leetcode.com/problems/middle-of-the-linked-list/)|[Python](./algorithms/middle-of-the-linked-list/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|880|[Decoded String at Index](https://leetcode.com/problems/decoded-string-at-index/)|[Python](./algorithms/decoded-string-at-index/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|881|[Boats to Save People](https://leetcode.com/problems/boats-to-save-people/)|[Python](./algorithms/boats-to-save-people/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|883|[Projection Area of 3D Shapes](https://leetcode.com/problems/projection-area-of-3d-shapes/)|[Java](./algorithms/projection-area-of-3d-shapes/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|884|[Uncommon Words from Two Sentences](https://leetcode.com/problems/uncommon-words-from-two-sentences/)|[Python](./algorithms/uncommon-words-from-two-sentences/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|885|[Spiral Matrix III](https://leetcode.com/problems/spiral-matrix-iii/)|[Python](./algorithms/spiral-matrix-iii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|888|[Fair Candy Swap](https://leetcode.com/problems/fair-candy-swap/)|[Python](./algorithms/fair-candy-swap/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|892|[Surface Area of 3D Shapes](https://leetcode.com/problems/surface-area-of-3d-shapes/)|[Python](./algorithms/surface-area-of-3d-shapes/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|893|[Groups of Special-Equivalent Strings](https://leetcode.com/problems/groups-of-special-equivalent-strings/)|[Python](./algorithms/groups-of-special-equivalent-strings/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|894|[All Possible Full Binary Trees](https://leetcode.com/problems/all-possible-full-binary-trees/)|[Python](./algorithms/all-possible-full-binary-trees/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|933|[Number of Recent Calls](https://leetcode.com/problems/number-of-recent-calls/)|[Python](./algorithms/number-of-recent-calls/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|958|[Check Completeness of a Binary Tree](https://leetcode.com/problems/check-completeness-of-a-binary-tree/)|[Python](./algorithms/check-completeness-of-a-binary-tree/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|1009|[Complement of Base 10 Integer](https://leetcode.com/problems/complement-of-base-10-integer/)|[Python](./algorithms/complement-of-base-10-integer/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|1029|[Check If It Is a Straight Line](https://leetcode.com/problems/check-if-it-is-a-straight-line/)|[Python](./algorithms/check-if-it-is-a-straight-line/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|1035|[Uncrossed Lines](https://leetcode.com/problems/uncrossed-lines/)|[Python](./algorithms/uncrossed-lines/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|1044|[Longest Duplicate Substring](https://leetcode.com/problems/longest-duplicate-substring/)|[Python](./algorithms/longest-duplicate-substring/)|![Hard](https://img.shields.io/badge/-Hard-red)|
-|1049|[Last Stone Weight II](https://leetcode.com/problems/last-stone-weight-ii/)|[Python](./algorithms/last-stone-weight-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|1071|[Greatest Common Divisor of Strings](https://leetcode.com/problems/greatest-common-divisor-of-strings/)|[Python](./algorithms/greatest-common-divisor-of-strings/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|1081|[Smallest Subsequence of Distinct Characters](https://leetcode.com/problems/smallest-subsequence-of-distinct-characters/)|[Python](./algorithms/smallest-subsequence-of-distinct-characters/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|1143|[Longest Common Subsequence](https://leetcode.com/problems/longest-common-subsequence/)|[Python](./algorithms/longest-common-subsequence/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|1232|[Check If It Is a Straight Line](https://leetcode.com/problems/check-if-it-is-a-straight-line/)|[Python](./algorithms/check-if-it-is-a-straight-line/)|![Easy](https://img.shields.io/badge/-Easy-green)|
-|1277|[Count Square Submatrices with All Ones](https://leetcode.com/problems/count-square-submatrices-with-all-ones/)|[Python](./algorithms/count-square-submatrices-with-all-ones/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|1288|[Remove Covered Intervals](https://leetcode.com/problems/remove-covered-intervals/)|[Python](./algorithms/remove-covered-intervals/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
-|1344|[Angle Between Hands of a Clock](https://leetcode.com/problems/angle-between-hands-of-a-clock/)|[Python](./algorithms/angle-between-hands-of-a-clock/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|1|[Two Sum](https://leetcode.com/problems/two-sum/)|[Java,Python](./questions/two-sum/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|2|[Add Two Numbers](https://leetcode.com/problems/add-two-numbers/)|[Java,Python](./questions/add-two-numbers/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|3|[Longest Substring Without Repeating Characters](https://leetcode.com/problems/longest-substring-without-repeating-characters/)|[Java,Python](./questions/longest-substring-without-repeating-characters/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|7|[Reverse Integer](https://leetcode.com/problems/reverse-integer/)|[Java](./questions/reverse-integer/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|8|[String to Integer (atoi)](https://leetcode.com/problems/string-to-integer-atoi/)|[Java,Python](./questions/string-to-integer/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|9|[Palindrome Number](https://leetcode.com/problems/palindrome-number/)|[Java](./questions/palindrome-number/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|11|[Container With Most Water](https://leetcode.com/problems/container-with-most-water/)|[Java,Python](./questions/container-with-most-water/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|12|[Integer to Roman](https://leetcode.com/problems/integer-to-roman/)|[Java](./questions/integer-to-roman/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|13|[Roman to Integer](https://leetcode.com/problems/roman-to-integer/)|[Java](./questions/roman-to-integer/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|14|[Longest Common Prefix](https://leetcode.com/problems/longest-common-prefix/)|[Java](./questions/longest-common-prefix/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|15|[3Sum](https://leetcode.com/problems/3sum/)|[Java,Python](./questions/3sum/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|16|[3Sum Closest](https://leetcode.com/problems/3sum-closest/)|[Java](./questions/3sum-closest/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|17|[Letter Combinations of a Phone Number](https://leetcode.com/problems/letter-combinations-of-a-phone-number/)|[Java](./questions/letter-combinations-of-a-phone-number/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|19|[Remove Nth Node From End of List](https://leetcode.com/problems/remove-nth-node-from-end-of-list/)|[Java](./questions/remove-nth-node-from-end-of-list/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|20|[Valid Parentheses](https://leetcode.com/problems/valid-parentheses/)|[Java](./questions/valid-parentheses/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|21|[Merge Two Sorted Lists](https://leetcode.com/problems/merge-two-sorted-lists/)|[Java,Python](./questions/merge-two-sorted-lists/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|22|[Generate Parentheses](https://leetcode.com/problems/generate-parentheses/)|[Java](./questions/generate-parentheses/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|23|[Merge k Sorted Lists](https://leetcode.com/problems/merge-k-sorted-lists/)|[Python](./questions/merge-k-sorted-lists/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|24|[Swap Nodes in Pairs](https://leetcode.com/problems/swap-nodes-in-pairs/)|[Java](./questions/swap-nodes-in-pairs/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|25|[Reverse Nodes in k-Group](https://leetcode.com/problems/reverse-nodes-in-k-group/)|[Python](./questions/reverse-nodes-in-k-group/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|26|[Remove Duplicates from Sorted Array](https://leetcode.com/problems/remove-duplicates-from-sorted-array/)|[Java](./questions/remove-duplicates-from-sorted-array/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|27|[Remove Element](https://leetcode.com/problems/remove-element/)|[Java](./questions/remove-element/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|28|[Implement strStr()](https://leetcode.com/problems/implement-strstr/)|[Java](./questions/implement-strstr/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|29|[Divide Two Integers](https://leetcode.com/problems/divide-two-integers/)|[Python](./questions/divide-two-integers/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|31|[Next Permutation](https://leetcode.com/problems/next-permutation/)|[Python](./questions/next-permutation/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|32|[Longest Valid Parentheses](https://leetcode.com/problems/longest-valid-parentheses/)|[Python](./questions/longest-valid-parentheses/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|33|[Search in Rotated Sorted Array](https://leetcode.com/problems/search-in-rotated-sorted-array/)|[Java,Python](./questions/search-in-rotated-sorted-array/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|34|[Find First and Last Position of Element in Sorted Array](https://leetcode.com/problems/find-first-and-last-position-of-element-in-sorted-array/)|[Python](./questions/find-first-and-last-position-of-element-in-sorted-array/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|35|[Search Insert Position](https://leetcode.com/problems/search-insert-position/)|[Java](./questions/search-insert-position/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|36|[Valid Sudoku](https://leetcode.com/problems/valid-sudoku/)|[Java](./questions/valid-sudoku/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|38|[Count and Say](https://leetcode.com/problems/count-and-say/)|[Java](./questions/count-and-say/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|39|[Combination Sum](https://leetcode.com/problems/combination-sum/)|[Java,Python](./questions/combination-sum/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|40|[Combination Sum II](https://leetcode.com/problems/combination-sum-ii/)|[Python](./questions/combination-sum-ii/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|41|[First Missing Positive](https://leetcode.com/problems/first-missing-positive/)|[Python](./questions/first-missing-positive/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|42|[Trapping Rain Water](https://leetcode.com/problems/trapping-rain-water/)|[Python](./questions/trapping-rain-water/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|43|[Multiply Strings](https://leetcode.com/problems/multiply-strings/)|[Java](./questions/multiply-strings/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|46|[Permutations](https://leetcode.com/problems/permutations/)|[Java,Python](./questions/permutations/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|47|[Permutations II](https://leetcode.com/problems/permutations-ii/)|[Python](./questions/permutations-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|48|[Rotate Image](https://leetcode.com/problems/rotate-image/)|[Python](./questions/rotate-image/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|49|[Group Anagrams](https://leetcode.com/problems/group-anagrams/)|[Python](./questions/group-anagrams/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|50|[Pow(x, n)](https://leetcode.com/problems/powx-n/)|[Java](./questions/pow(x,n)/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|53|[Maximum Subarray](https://leetcode.com/problems/maximum-subarray/)|[Java,Python](./questions/maximum-subarray/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|54|[Spiral Matrix](https://leetcode.com/problems/spiral-matrix/)|[Java,Python](./questions/spiral-matrix/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|55|[Jump Game](https://leetcode.com/problems/jump-game/)|[Java](./questions/jump-game/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|56|[Merge Intervals](https://leetcode.com/problems/merge-intervals/)|[Python](./questions/merge-intervals/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|56|[Insert Interval](https://leetcode.com/problems/insert-interval/)|[Python](./questions/insert-interval/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|58|[Length of Last Word](https://leetcode.com/problems/length-of-last-word/)|[Java](./questions/length-of-last-word/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|59|[Spiral Matrix II](https://leetcode.com/problems/spiral-matrix-ii/)|[Python](./questions/spiral-matrix-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|60|[Permutation Sequence](https://leetcode.com/problems/permutation-sequence/)|[Python](./questions/permutation-sequence/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|61|[Rotate List](https://leetcode.com/problems/rotate-list/)|[Java,Python](./questions/rotate-list/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|62|[Unique Paths](https://leetcode.com/problems/unique-paths/)|[Python](./questions/unique-paths/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|63|[Unique Paths II](https://leetcode.com/problems/unique-paths-ii/)|[Python](./questions/unique-paths-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|64|[Minimum Path Sum](https://leetcode.com/problems/minimum-path-sum/)|[Python](./questions/minimum-path-sum/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|66|[Plus One](https://leetcode.com/problems/plus-one/)|[Java](./questions/plus-one/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|67|[Add Binary](https://leetcode.com/problems/add-binary/)|[Java](./questions/add-binary/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|69|[Sqrt(x)](https://leetcode.com/problems/sqrtx/)|[C++,Python](./questions/sqrtx/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|70|[Climbing Stairs](https://leetcode.com/problems/climbing-stairs/)|[Java](./questions/climbing-stairs/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|71|[Simplify Path](https://leetcode.com/problems/simplify-path/)|[Python](./questions/simplify-path/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|72|[Edit Distance](https://leetcode.com/problems/edit-distance/)|[Java,C++](./questions/edit-distance/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|73|[Set Matrix Zeroes](https://leetcode.com/problems/set-matrix-zeroes/)|[Java](./questions/set-matrix-zeroes/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|74|[Search a 2D Matrix](https://leetcode.com/problems/search-a-2d-matrix/)|[Java](./questions/search-a-2d-matrix/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|75|[Sort Colors](https://leetcode.com/problems/sort-colors/)|[Java,Python](./questions/sort-colors/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|76|[Minimum Window Substring](https://leetcode.com/problems/minimum-window-substring/)|[Python](./questions/minimum-window-substring/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|77|[Combinations](https://leetcode.com/problems/combinations/)|[Java,Python](./questions/combinations/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|78|[Subsets](https://leetcode.com/problems/subsets/)|[Python](./questions/subsets/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|79|[Word Search](https://leetcode.com/problems/word-search/)|[Python](./questions/word-search/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|80|[Remove Duplicates from Sorted Array II](https://leetcode.com/problems/remove-duplicates-from-sorted-array-ii/)|[Java](./questions/remove-duplicates-from-sorted-array-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|81|[Search in Rotated Sorted Array II](https://leetcode.com/problems/search-in-rotated-sorted-array-ii/)|[Python](./questions/search-in-rotated-sorted-array-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|82|[Remove Duplicates from Sorted List II](https://leetcode.com/problems/remove-duplicates-from-sorted-list-ii/)|[C++,Java,Python](./questions/remove-duplicates-from-sorted-list-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|83|[Remove Duplicates from Sorted List](https://leetcode.com/problems/remove-duplicates-from-sorted-list/)|[Java](./questions/remove-duplicates-from-sorted-list/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|84|[Largest Rectangle in Histogram](https://leetcode.com/problems/largest-rectangle-in-histogram/)|[Python](./questions/largest-rectangle-in-histogram/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|85|[Maximal Rectangle](https://leetcode.com/problems/maximal-rectangle/)|[Python](./questions/maximal-rectangle/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|86|[Partition List](https://leetcode.com/problems/partition-list/)|[Python](./questions/partition-list/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|88|[Merge Sorted Array](https://leetcode.com/problems/merge-sorted-array/)|[Java](./questions/merge-sorted-array/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|92|[Reverse Linked List II](https://leetcode.com/problems/reverse-linked-list-ii/)|[Java](./questions/reverse-linked-list-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|98|[Validate Binary Search Tree](https://leetcode.com/problems/validate-binary-search-tree/)|[Java](./questions/validate-binary-search-tree/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|100|[Same Tree](https://leetcode.com/problems/same-tree/)|[Java](./questions/same-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|101|[Symmetric Tree](https://leetcode.com/problems/symmetric-tree/)|[Java](./questions/symmetric-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|102|[Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/)|[Java,Python](./questions/binary-tree-level-order-traversal/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|103|[Binary Tree Zigzag Level Order Traversal](https://leetcode.com/problems/binary-tree-zigzag-level-order-traversal/)|[Python](./questions/binary-tree-zigzag-level-order-traversal/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|104|[Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree/)|[Java,Python](./questions/maximum-depth-of-binary-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|105|[Construct Binary Tree from Preorder and Inorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/)|[Python](./questions/construct-binary-tree-from-preorder-and-inorder-traversal/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|106|[Construct Binary Tree from Inorder and Postorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal/)|[Python](./questions/construct-binary-tree-from-inorder-and-postorder-traversal/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|107|[Binary Tree Level Order Traversal II](https://leetcode.com/problems/binary-tree-level-order-traversal-ii/)|[Java](./questions/binary-tree-level-order-traversal-ii/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|108|[Convert Sorted Array to Binary Search Tree](https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/)|[Python](./questions/convert-sorted-array-to-binary-search-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|109|[Convert Sorted List to Binary Search Tree](https://leetcode.com/problems/convert-sorted-list-to-binary-search-tree)|[Python](./questions/convert-sorted-list-to-binary-search-tree/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|110|[Balanced Binary Tree](https://leetcode.com/problems/balanced-binary-tree/)|[Java](./questions/balanced-binary-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|111|[Minimum Depth of Binary Tree](https://leetcode.com/problems/minimum-depth-of-binary-tree/)|[Java](./questions/minimum-depth-of-binary-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|112|[Path Sum](https://leetcode.com/problems/path-sum/)|[Java,Python](./questions/path-sum/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|113|[Path Sum II](https://leetcode.com/problems/path-sum-ii/)|[Java,Python](./questions/path-sum-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|118|[Pascal's Triangle](https://leetcode.com/problems/pascals-triangle/)|[Java](./questions/pascals-triangle/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|119|[Pascal's Triangle II](https://leetcode.com/problems/pascals-triangle-ii/)|[Java](./questions/pascals-triangle-ii/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|121|[Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/)|[Python](./questions/best-time-to-buy-and-sell-stock/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|125|[Valid Palindrome](https://leetcode.com/problems/valid-palindrome/)|[Java](./questions/valid-palindrome/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|127|[Word Ladder](https://leetcode.com/problems/word-ladder/)|[Python,Java](./questions/word-ladder/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|129|[Sum Root to Leaf Numbers](https://leetcode.com/problems/sum-root-to-leaf-numbers/)|[Java](./questions/sum-root-to-leaf-numbers/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|131|[Palindrome Partitioning](https://leetcode.com/problems/palindrome-partitioning/)|[Python](./questions/palindrome-partitioning/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|134|[Gas Station](https://leetcode.com/problems/gas-station/)|[Python](./questions/gas-station/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|135|[Candy](https://leetcode.com/problems/candy/)|[Python](./questions/candy/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|136|[Single Number](https://leetcode.com/problems/single-number/)|[Java](./questions/single-number/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|137|[Single Number II](https://leetcode.com/problems/single-number-ii/)|[Java](./questions/single-number-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|138|[Copy List with Random Pointer](https://leetcode.com/problems/copy-list-with-random-pointer/)|[Java](./questions/copy-list-with-random-pointer/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|139|[Word Break](https://leetcode.com/problems/word-break/)|[Java](./questions/word-break/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|141|[Linked List Cycle](https://leetcode.com/problems/linked-list-cycle/)|[Java](./questions/linked-list-cycle/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|142|[Linked List Cycle II](https://leetcode.com/problems/linked-list-cycle-ii/)|[Java](./questions/linked-list-cycle-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|144|[Binary Tree Preorder Traversal](https://leetcode.com/problems/binary-tree-preorder-traversal/)|[Python](./questions/binary-tree-preorder-traversal/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|145|[Binary Tree Postorder Traversal](https://leetcode.com/problems/binary-tree-postorder-traversal/)|[Python](./questions/binary-tree-postorder-traversal/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|146|[LRU Cache](https://leetcode.com/problems/lru-cache/)|[Python](./questions/lru-cache/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|147|[Insertion Sort List](https://leetcode.com/problems/insertion-sort-list/)|[Python](./questions/insertion-sort-list/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|148|[Sort List](https://leetcode.com/problems/sort-list/)|[Python](./questions/sort-list/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|149|[Max Points on a Line](https://leetcode.com/problems/max-points-on-a-line/)|[Java](./questions/max-points-on-a-line/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|150|[Evaluate Reverse Polish Notation](https://leetcode.com/problems/evaluate-reverse-polish-notation/)|[Python](./questions/evaluate-reverse-polish-notation/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|151|[Reverse Words in a String](https://leetcode.com/problems/reverse-words-in-a-string/)|[Python](./questions/reverse-words-in-a-string/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|152|[Maximum Product Subarray](https://leetcode.com/problems/maximum-product-subarray/)|[Python](./questions/maximum-product-subarray/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|153|[Find Minimum in Rotated Sorted Array](https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/)|[Python](./questions/find-minimum-in-rotated-sorted-array/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|155|[Min Stack](https://leetcode.com/problems/min-stack/)|[Java,Python](./questions/min-stack/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|160|[Intersection of Two Linked Lists](https://leetcode.com/problems/intersection-of-two-linked-lists/)|[Java,Python](./questions/intersection-of-two-linked-lists/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|162|[Find Peak Element](https://leetcode.com/problems/find-peak-element/)|[Java,Python](./questions/find-peak-element/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|165|[Compare Version Numbers](https://leetcode.com/problems/compare-version-numbers/)|[Java,Python](./questions/compare-version-numbers/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|166|[Fraction to Recurring Decimal](https://leetcode.com/problems/fraction-to-recurring-decimal/)|[Python](./questions/fraction-to-recurring-decimal/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|167|[Two Sum II - Input array is sorted](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/)|[Python](./questions/two-sum-ii-input-array-is-sorted/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|168|[Excel Sheet Column Title](https://leetcode.com/problems/excel-sheet-column-title/)|[Python](./questions/excel-sheet-column-title/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|169|[Majority Element](https://leetcode.com/problems/majority-element/)|[Java,Python](./questions/majority-element/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|171|[Excel Sheet Column Number](https://leetcode.com/problems/excel-sheet-column-number/)|[Python](./questions/excel-sheet-column-number/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|172|[Factorial Trailing Zeroes](https://leetcode.com/problems/factorial-trailing-zeroes/)|[Python](./questions/factorial-trailing-zeroes/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|173|[Binary Search Tree Iterator](https://leetcode.com/problems/binary-search-tree-iterator/)|[Python](./questions/binary-search-tree-iterator/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|175|[Combine Two Tables](https://leetcode.com/problems/combine-two-tables/)|[SQL](./questions/combine-two-tables/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|176|[Second Highest Salary](https://leetcode.com/problems/second-highest-salary/)|[SQL](./questions/second-highest-salary/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|177|[Nth Highest Salary](https://leetcode.com/problems/nth-highest-salary/)|[SQL](./questions/nth-highest-salary/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|178|[Rank Scores](https://leetcode.com/problems/rank-scores/)|[SQL](./questions/rank-scores/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|179|[Largest Number](https://leetcode.com/problems/largest-number/)|[Python](./questions/largest-number/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|180|[Consecutive Numbers](https://leetcode.com/problems/consecutive-numbers/)|[SQL](./questions/consecutive-numbers/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|181|[Employees Earning More Than Their Managers](https://leetcode.com/problems/employees-earning-more-than-their-managers/)|[SQL](./questions/employees-earning-more-than-their-managers/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|182|[Duplicate Emails](https://leetcode.com/problems/duplicate-emails/)|[SQL](./questions/duplicate-emails/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|183|[Customers Who Never Order](https://leetcode.com/problems/customers-who-never-order/)|[SQL](./questions/customers-who-never-order/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|184|[Department Highest Salary](https://leetcode.com/problems/department-highest-salary/)|[SQL](./questions/department-highest-salary/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|185|[Department Top Three Salaries](https://leetcode.com/problems/department-top-three-salaries/)|[SQL](./questions/department-top-three-salaries/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|187|[Repeated DNA Sequences](https://leetcode.com/problems/repeated-dna-sequences/)|[Java,Python](./questions/repeated-dna-sequences/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|188|[Best Time to Buy and Sell Stock IV](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-iv/)|[Python](./questions/best-time-to-buy-and-sell-stock-iv/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|189|[Rotate Array](https://leetcode.com/problems/rotate-array/)|[Java,Python](./questions/rotate-array/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|190|[Reverse Bits](https://leetcode.com/problems/reverse-bits/)|[Java,Python](./questions/reverse-bits/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|191|[Number of 1 Bits](https://leetcode.com/problems/number-of-1-bits/)|[Java,Python](./questions/number-of-1-bits/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|192|[Word Frequency](https://leetcode.com/problems/word-frequency/)|[Shell](./questions/word-frequency/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|193|[Valid Phone Numbers](https://leetcode.com/problems/valid-phone-numbers/)|[Shell](./questions/valid-phone-numbers/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|194|[Transpose File](https://leetcode.com/problems/transpose-file/)|[Shell](./questions/transpose-file/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|195|[Tenth Line](https://leetcode.com/problems/tenth-line/)|[Shell](./questions/tenth-line/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|196|[Delete Duplicate Emails](https://leetcode.com/problems/delete-duplicate-emails/)|[SQL](./questions/delete-duplicate-emails/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|197|[Rising Temperature](https://leetcode.com/problems/rising-temperature/)|[SQL](./questions/rising-temperature/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|198|[House Robber](https://leetcode.com/problems/house-robber/)|[Java,Python](./questions/house-robber/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|199|[Binary Tree Right Side View](https://leetcode.com/problems/binary-tree-right-side-view/)|[Python](./questions/binary-tree-right-side-view/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|200|[Number of Islands](https://leetcode.com/problems/number-of-islands)|[Python](./questions/number-of-islands/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|201|[Bitwise AND of Numbers Range](https://leetcode.com/problems/bitwise-and-of-numbers-range)|[Python](./questions/bitwise-and-of-numbers-range/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|202|[Happy Number](https://leetcode.com/problems/happy-number/)|[Java](./questions/happy-number/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|203|[Remove Linked List Elements](https://leetcode.com/problems/remove-linked-list-elements/)|[Java,Python](./questions/remove-linked-list-elements/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|204|[Count Primes](https://leetcode.com/problems/count-primes/)|[Python](./questions/count-primes/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|205|[Isomorphic Strings](https://leetcode.com/problems/isomorphic-strings/)|[Java,Python](./questions/isomorphic-strings/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|206|[Reverse Linked List](https://leetcode.com/problems/reverse-linked-list/)|[Java,Python](./questions/reverse-linked-list/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|207|[Course Schedule](https://leetcode.com/problems/course-schedule/)|[Python](./questions/course-schedule/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|208|[Implement Trie (Prefix Tree)](https://leetcode.com/problems/implement-trie-prefix-tree/)|[Python](./questions/implement-trie-prefix-tree/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|209|[Minimum Size Subarray Sum](https://leetcode.com/problems/minimum-size-subarray-sum/)|[Python](./questions/minimum-size-subarray-sum/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|210|[Course Schedule II](https://leetcode.com/problems/course-schedule-ii/)|[Python](./questions/course-schedule-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|211|[Add and Search Word - Data structure design](https://leetcode.com/problems/add-and-search-word-data-structure-design/)|[Python](./questions/add-and-search-word-data-structure-design/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|212|[Word Search II](https://leetcode.com/problems/word-search-ii/)|[Python](./questions/word-search-ii/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|213|[House Robber II](https://leetcode.com/problems/house-robber-ii/)|[Python](./questions/house-robber-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|215|[Kth Largest Element in an Array](https://leetcode.com/problems/kth-largest-element-in-an-array/)|[Python](./questions/kth-largest-element-in-an-array/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|216|[Combination Sum III](https://leetcode.com/problems/combination-sum-iii/)|[Python](./questions/combination-sum-iii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|217|[Contains Duplicate](https://leetcode.com/problems/contains-duplicate/)|[Java,Python](./questions/contains-duplicate/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|218|[The Skyline Problem](https://leetcode.com/problems/the-skyline-problem/)|[Python](./questions/the-skyline-problem/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|219|[Contains Duplicate II](https://leetcode.com/problems/contains-duplicate-ii/)|[Java,Python](./questions/contains-duplicate-ii/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|220|[Contains Duplicate III](https://leetcode.com/problems/contains-duplicate-iii/)|[Python](./questions/contains-duplicate-iii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|221|[Maximal Square](https://leetcode.com/problems/maximal-square/)|[Python](./questions/maximal-square/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|222|[Count Complete Tree Nodes](https://leetcode.com/problems/count-complete-tree-nodes/)|[Python](./questions/count-complete-tree-nodes/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|226|[Implement Stack using Queues](https://leetcode.com/problems/implement-stack-using-queues/)|[Python](./questions/implement-stack-using-queues/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|227|[Basic Calculator II](https://leetcode.com/problems/basic-calculator-ii/)|[Python](./questions/basic-calculator-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|228|[Summary Ranges](https://leetcode.com/problems/summary-ranges/)|[Java,Python](./questions/summary-ranges/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|229|[Majority Element II](https://leetcode.com/problems/majority-element-ii/)|[Java,Python](./questions/majority-element-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|230|[Kth Smallest Element in a BST](https://leetcode.com/problems/kth-smallest-element-in-a-bst/)|[Python](./questions/kth-smallest-element-in-a-bst/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|231|[Power of Two](https://leetcode.com/problems/power-of-two/)|[Python](./questions/power-of-two/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|232|[Implement Queue using Stacks](https://leetcode.com/problems/implement-queue-using-stacks/)|[Python](./questions/implement-queue-using-stacks/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|233|[Number of Digit One](https://leetcode.com/problems/number-of-digit-one/)|[C++,Python](./questions/number-of-digit-one/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|234|[Palindrome Linked List](https://leetcode.com/problems/palindrome-linked-list/)|[Java,Python](./questions/palindrome-linked-list/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|235|[Lowest Common Ancestor of a Binary Search Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/)|[Java,Python](./questions/lowest-common-ancestor-of-a-binary-search-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|236|[Lowest Common Ancestor of a Binary Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/)|[Python](./questions/lowest-common-ancestor-of-a-binary-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|237|[Delete Node in a Linked List](https://leetcode.com/problems/delete-node-in-a-linked-list/)|[C++,Python](./questions/delete-node-in-a-linked-list/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|238|[Product of Array Except Self](https://leetcode.com/problems/product-of-array-except-self/)|[Python](./questions/product-of-array-except-self/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|242|[Valid Anagram](https://leetcode.com/problems/valid-anagram/)|[Java](./questions/valid-anagram/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|257|[Binary Tree Paths](https://leetcode.com/problems/binary-tree-paths/)|[Java](./questions/binary-tree-paths/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|258|[Add Digits](https://leetcode.com/problems/add-digits/)|[C++](./questions/add-digits/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|260|[Single Number III](https://leetcode.com/problems/single-number-iii/)|[Java](./questions/single-number-iii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|262|[Trips and Users](https://leetcode.com/problems/trips-and-users/)|[SQL](./questions/trips-and-users/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|263|[Ugly Number](https://leetcode.com/problems/ugly-number/)|[Java](./questions/ugly-number/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|264|[Ugly Number II](https://leetcode.com/problems/ugly-number-ii/)|[Java](./questions/ugly-number-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|268|[Missing Number](https://leetcode.com/problems/missing-number/)|[Java](./questions/missing-number/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|273|[Integer to English Words](https://leetcode.com/problems/integer-to-english-words/)|[Java](./questions/integer-to-english-words/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|274|[H-Index](https://leetcode.com/problems/h-index/)|[Java](./questions/h-index/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|275|[H-Index II](https://leetcode.com/problems/h-index-ii/)|[Java](./questions/h-index-2/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|279|[Perfect Squares](https://leetcode.com/problems/perfect-squares/)|[Java](./questions/perfect-squares/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|283|[Move Zeroes](https://leetcode.com/problems/move-zeroes/)|[C++](./questions/move-zeroes/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|284|[Peeking Iterator](https://leetcode.com/problems/peeking-iterator/)|[Java](./questions/peeking-iterator/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|287|[Find the Duplicate Number](https://leetcode.com/problems/find-the-duplicate-number/)|[Java,Python](./questions/find-the-duplicate-number/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|290|[Word Pattern](https://leetcode.com/problems/word-pattern/)|[Java](./questions/word-pattern/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|292|[Nim Game](https://leetcode.com/problems/nim-game/)|[C++](./questions/nim-game/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|295|[Find Median from Data Stream](https://leetcode.com/problems/find-median-from-data-stream/)|[Java](./questions/find-median-from-data-stream/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|299|[Bulls and Cows](https://leetcode.com/problems/bulls-and-cows/)|[Java](./questions/bulls-and-cows/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|300|[Longest Increasing Subsequence](https://leetcode.com/problems/longest-increasing-subsequence/)|[Java](./questions/longest-increasing-subsequence/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|303|[Range Sum Query - Immutable](https://leetcode.com/problems/range-sum-query-immutable/)|[Java](./questions/range-sum-query-immutable/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|304|[Range Sum Query 2D - Immutable](https://leetcode.com/problems/range-sum-query-2d-immutable/)|[Java](./questions/range-sum-query-2d-immutable/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|316|[Remove Duplicate Letters](https://leetcode.com/problems/remove-duplicate-letters/)|[Python](./questions/remove-duplicate-letters/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|317|[Shortest Distance from All Buildings](https://leetcode.com/problems/shortest-distance-from-all-buildings/)|[Python](./questions/shortest-distance-from-all-buildings/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|328|[Odd Even Linked List](https://leetcode.com/problems/odd-even-linked-list/)|[Java](./questions/odd-even-linked-list/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|330|[Patching Array](https://leetcode.com/problems/patching-array/)|[Java](./questions/patching-array/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|338|[Counting Bits](https://leetcode.com/problems/counting-bits/)|[Java](./questions/counting-bits/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|344|[Reverse String](https://leetcode.com/problems/reverse-string/)|[Java](./questions/reverse-string/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|367|[Valid Perfect Square](https://leetcode.com/problems/valid-perfect-square/)|[C++](./questions/valid-perfect-square/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|371|[Sum of Two Integers](https://leetcode.com/problems/sum-of-two-integers/)|[Java](./questions/sum-of-two-integers/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|389|[Find the Difference](https://leetcode.com/problems/find-the-difference/)|[Python](./questions/find-the-difference/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|392|[Is Subsequence](https://leetcode.com/problems/is-subsequence/)|[Java,Python](./questions/is-subsequence/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|394|[Decode String](https://leetcode.com/problems/decode-string/)|[Python](./questions/decode-string/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|437|[Path Sum III](https://leetcode.com/problems/path-sum-iii/)|[Java](./questions/path-sum-iii/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|438|[Find All Anagrams in a String](https://leetcode.com/problems/find-all-anagrams-in-a-string/)|[Java](./questions/find-all-anagrams-in-a-string/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|445|[Add Two Numbers II](https://leetcode.com/problems/add-two-numbers-ii/)|[Python](./questions/add-two-numbers-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|448|[Find All Numbers Disappeared in an Array](https://leetcode.com/problems/find-all-numbers-disappeared-in-an-array/)|[Java](./questions/find-all-numbers-disappeared-in-an-array/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|449|[Serialize and Deserialize BST](https://leetcode.com/problems/serialize-and-deserialize-bst/)|[Python](./questions/serialize-and-deserialize-bst/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|452|[Minimum Number of Arrows to Burst Balloons](https://leetcode.com/problems/minimum-number-of-arrows-to-burst-balloons/)|[Python](./questions/minimum-number-of-arrows-to-burst-balloons/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|461|[Hamming Distance](https://leetcode.com/problems/hamming-distance/)|[Java](./questions/hamming-distance/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|485|[Max Consecutive Ones](https://leetcode.com/problems/max-consecutive-ones/)|[Java](./questions/max-consecutive-ones/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|496|[Next Greater Element I](https://leetcode.com/problems/next-greater-element-i/)|[Python](./questions/next-greater-element-i/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|500|[Keyboard Row](https://leetcode.com/problems/keyboard-row/)|[Python](./questions/keyboard-row/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|503|[Next Greater Element II](https://leetcode.com/problems/next-greater-element-ii/)|[Java](./questions/next-greater-element-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|532|[K-diff Pairs in an Array](https://leetcode.com/problems/k-diff-pairs-in-an-array/)|[Python](./questions/k-diff-pairs-in-an-array/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|538|[Convert BST to Greater Tree](https://leetcode.com/problems/convert-bst-to-greater-tree/)|[Java](./questions/convert-bst-to-greater-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|543|[Diameter of Binary Tree](https://leetcode.com/problems/diameter-of-binary-tree/)|[Java,Python](./questions/diameter-of-binary-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|560|[Subarray Sum Equals K](https://leetcode.com/problems/subarray-sum-equals-k/)|[Java](./questions/subarray-sum-equals-k/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|561|[Array Partition I](https://leetcode.com/problems/array-partition-i/)|[Python](./questions/array-partition-i/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|572|[Subtree of Another Tree](https://leetcode.com/problems/subtree-of-another-tree/)|[Java](./questions/subtree-of-another-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|581|[Shortest Unsorted Continuous Subarray](https://leetcode.com/problems/shortest-unsorted-continuous-subarray/)|[Java](./questions/shortest-unsorted-continuous-subarray/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|595|[Big Countries](https://leetcode.com/problems/big-countries/)|[SQL](./questions/big-countries/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|596|[Classes More Than 5 Students](https://leetcode.com/problems/classes-more-than-5-students/)|[SQL](./questions/classes-more-than-5-students/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|601|[Human Traffic of Stadium](https://leetcode.com/problems/human-traffic-of-stadium/)|[SQL](./questions/human-traffic-of-stadium/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|605|[Can Place Flowers](https://leetcode.com/problems/can-place-flowers/)|[Java](./questions/can-place-flowers/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|617|[Merge Two Binary Trees](https://leetcode.com/problems/merge-two-binary-trees/)|[Java](./questions/merge-two-binary-trees/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|620|[Not Boring Movies](https://leetcode.com/problems/not-boring-movies/)|[SQL](./questions/not-boring-movies/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|626|[Exchange Seats](https://leetcode.com/problems/exchange-seats/)|[SQL](./questions/exchange-seats/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|627|[Swap Salary](https://leetcode.com/problems/swap-salary/)|[SQL](./questions/swap-salary/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|643|[Maximum Average Subarray I](https://leetcode.com/problems/maximum-average-subarray-i/)|[Python](./questions/maximum-average-subarray-i/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|645|[Set Mismatch](https://leetcode.com/problems/set-mismatch/)|[Python](./questions/set-mismatch/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|653|[Two Sum IV - Input is a BST](https://leetcode.com/problems/two-sum-iv-input-is-a-bst/)|[Python](./questions/two-sum-iv-input-is-a-bst/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|657|[Judge Route Circle](https://leetcode.com/problems/judge-route-circle/)|[Python](./questions/judge-route-circle/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|661|[Image Smoother](https://leetcode.com/problems/image-smoother/)|[Python](./questions/image-smoother/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|665|[Non-decreasing Array](https://leetcode.com/problems/non-decreasing-array/)|[Python](./questions/non-decreasing-array/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|669|[Trim a Binary Search Tree](https://leetcode.com/problems/trim-a-binary-search-tree/)|[Python](./questions/trim-a-binary-search-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|670|[Maximum Swap](https://leetcode.com/problems/maximum-swap/)|[Python](./questions/maximum-swap/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|671|[Second Minimum Node In a Binary Tree](https://leetcode.com/problems/second-minimum-node-in-a-binary-tree/)|[Python](./questions/second-minimum-node-in-a-binary-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|674|[Longest Continuous Increasing Subsequence](https://leetcode.com/problems/longest-continuous-increasing-subsequence/)|[Python](./questions/longest-continuous-increasing-subsequence/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|680|[Valid Palindrome II](https://leetcode.com/problems/valid-palindrome-ii/)|[Python](./questions/valid-palindrome-ii/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|682|[Baseball Game](https://leetcode.com/problems/baseball-game/)|[Python](./questions/baseball-game/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|686|[Repeated String Match](https://leetcode.com/problems/repeated-string-match/)|[Python](./questions/repeated-string-match/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|687|[Longest Univalue Path](https://leetcode.com/problems/longest-univalue-path/)|[Python](./questions/longest-univalue-path/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|690|[Employee Importance](https://leetcode.com/problems/employee-importance/)|[Python](./questions/employee-importance/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|693|[Binary Number with Alternating Bits](https://leetcode.com/problems/binary-number-with-alternating-bits/)|[Python](./questions/binary-number-with-alternating-bits/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|695|[Max Area of Island](https://leetcode.com/problems/max-area-of-island/)|[Python](./questions/max-area-of-island/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|696|[Count Binary Substrings](https://leetcode.com/problems/count-binary-substrings/)|[Python](./questions/count-binary-substrings/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|697|[Degree of an Array](https://leetcode.com/problems/degree-of-an-array/)|[Python](./questions/degree-of-an-array/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|700|[Search in a Binary Search Tree](https://leetcode.com/problems/search-in-a-binary-search-tree/)|[Python](./questions/search-in-a-binary-search-tree/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|701|[Insert into a Binary Search Tree](https://leetcode.com/problems/insert-into-a-binary-search-tree/)|[Python](./questions/insert-into-a-binary-search-tree/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|704|[Binary Search](https://leetcode.com/problems/binary-search/)|[Python](./questions/binary-search/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|705|[Design HashSet](https://leetcode.com/problems/design-hashset/)|[Python](./questions/design-hashset/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|706|[Design HashMap](https://leetcode.com/problems/design-hashmap/)|[Python](./questions/design-hashmap/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|707|[Design Linked List](https://leetcode.com/problems/design-linked-list/)|[Python](./questions/design-linked-list/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|709|[To Lower Case](https://leetcode.com/problems/to-lower-case/)|[Python](./questions/to-lower-case/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|717|[1-bit and 2-bit Characters](https://leetcode.com/problems/1-bit-and-2-bit-characters/)|[Python](./questions/1-bit-and-2-bit-characters/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|720|[Longest Word in Dictionary](https://leetcode.com/problems/longest-word-in-dictionary/)|[Python](./questions/longest-word-in-dictionary/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|724|[Find Pivot Index](https://leetcode.com/problems/find-pivot-index/)|[Python](./questions/find-pivot-index/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|728|[Self Dividing Numbers](https://leetcode.com/problems/self-dividing-numbers/)|[Python](./questions/self-dividing-numbers/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|733|[Flood Fill](https://leetcode.com/problems/flood-fill/)|[Python](./questions/flood-fill/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|744|[Find Smallest Letter Greater Than Target](https://leetcode.com/problems/find-smallest-letter-greater-than-target/)|[Python](./questions/find-smallest-letter-greater-than-target/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|746|[Min Cost Climbing Stairs](https://leetcode.com/problems/min-cost-climbing-stairs/)|[Python](./questions/min-cost-climbing-stairs/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|747|[Largest Number At Least Twice of Others](https://leetcode.com/problems/largest-number-at-least-twice-of-others/)|[Python](./questions/largest-number-at-least-twice-of-others/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|762|[Prime Number of Set Bits in Binary Representation](https://leetcode.com/problems/prime-number-of-set-bits-in-binary-representation/)|[Python](./questions/prime-number-of-set-bits-in-binary-representation/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|766|[Toeplitz Matrix](https://leetcode.com/problems/toeplitz-matrix/)|[Python](./questions/toeplitz-matrix/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|771|[Jewels and Stones](https://leetcode.com/problems/jewels-and-stones/)|[Python](./questions/jewels-and-stones/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|784|[Letter Case Permutation](https://leetcode.com/problems/letter-case-permutation/)|[Python](./questions/letter-case-permutation/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|788|[Rotated Digits](https://leetcode.com/problems/rotated-digits/)|[Python](./questions/rotated-digits/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|796|[Rotate String](https://leetcode.com/problems/rotate-string/)|[Python](./questions/rotate-string/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|804|[Unique Morse Code Words](https://leetcode.com/problems/unique-morse-code-words/)|[Python](./questions/unique-morse-code-words/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|806|[Number of Lines To Write String](https://leetcode.com/problems/number-of-lines-to-write-string/)|[Python](./questions/number-of-lines-to-write-string/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|811|[Subdomain Visit Count](https://leetcode.com/problems/subdomain-visit-count/)|[Python](./questions/subdomain-visit-count/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|812|[Largest Triangle Area](https://leetcode.com/problems/largest-triangle-area/)|[Python](./questions/largest-triangle-area/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|819|[Most Common Word](https://leetcode.com/problems/most-common-word/)|[Python](./questions/most-common-word/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|821|[Shortest Distance to a Character](https://leetcode.com/problems/shortest-distance-to-a-character/)|[Python](./questions/shortest-distance-to-a-character/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|824|[Goat Latin](https://leetcode.com/problems/goat-latin/)|[Python](./questions/goat-latin/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|830|[Positions of Large Groups](https://leetcode.com/problems/positions-of-large-groups/)|[Python](./questions/positions-of-large-groups/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|832|[Flipping an Image](https://leetcode.com/problems/flipping-an-image/)|[Java](./questions/flipping-an-image/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|836|[Rectangle Overlap](https://leetcode.com/problems/rectangle-overlap/)|[Python](./questions/rectangle-overlap/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|840|[Magic Squares In Grid](https://leetcode.com/problems/magic-squares-in-grid/)|[Python](./questions/magic-squares-in-grid/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|844|[Backspace String Compare](https://leetcode.com/problems/backspace-string-compare/)|[Python](./questions/backspace-string-compare/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|849|[Maximize Distance to Closest Person](https://leetcode.com/problems/maximize-distance-to-closest-person/)|[Python](./questions/maximize-distance-to-closest-person/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|852|[Peak Index in a Mountain Array](https://leetcode.com/problems/peak-index-in-a-mountain-array/)|[Python](./questions/peak-index-in-a-mountain-array/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|859|[Buddy Strings](https://leetcode.com/problems/buddy-strings/)|[Python](./questions/buddy-strings/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|860|[Lemonade Change](https://leetcode.com/problems/lemonade-change/)|[Python](./questions/lemonade-change/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|867|[Binary Gap](https://leetcode.com/problems/binary-gap/)|[Python](./questions/binary-gap/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|868|[Transpose Matrix](https://leetcode.com/problems/transpose-matrix/)|[Python](./questions/transpose-matrix/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|872|[Leaf-Similar Trees](https://leetcode.com/problems/leaf-similar-trees/)|[Java](./questions/leaf-similar-trees/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|874|[Walking Robot Simulation](https://leetcode.com/problems/walking-robot-simulation/)|[Java](./questions/walking-robot-simulation/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|876|[Middle of the Linked List](https://leetcode.com/problems/middle-of-the-linked-list/)|[Python](./questions/middle-of-the-linked-list/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|880|[Decoded String at Index](https://leetcode.com/problems/decoded-string-at-index/)|[Python](./questions/decoded-string-at-index/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|881|[Boats to Save People](https://leetcode.com/problems/boats-to-save-people/)|[Python](./questions/boats-to-save-people/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|883|[Projection Area of 3D Shapes](https://leetcode.com/problems/projection-area-of-3d-shapes/)|[Java](./questions/projection-area-of-3d-shapes/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|884|[Uncommon Words from Two Sentences](https://leetcode.com/problems/uncommon-words-from-two-sentences/)|[Python](./questions/uncommon-words-from-two-sentences/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|885|[Spiral Matrix III](https://leetcode.com/problems/spiral-matrix-iii/)|[Python](./questions/spiral-matrix-iii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|888|[Fair Candy Swap](https://leetcode.com/problems/fair-candy-swap/)|[Python](./questions/fair-candy-swap/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|892|[Surface Area of 3D Shapes](https://leetcode.com/problems/surface-area-of-3d-shapes/)|[Python](./questions/surface-area-of-3d-shapes/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|893|[Groups of Special-Equivalent Strings](https://leetcode.com/problems/groups-of-special-equivalent-strings/)|[Python](./questions/groups-of-special-equivalent-strings/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|894|[All Possible Full Binary Trees](https://leetcode.com/problems/all-possible-full-binary-trees/)|[Python](./questions/all-possible-full-binary-trees/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|933|[Number of Recent Calls](https://leetcode.com/problems/number-of-recent-calls/)|[Python](./questions/number-of-recent-calls/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|958|[Check Completeness of a Binary Tree](https://leetcode.com/problems/check-completeness-of-a-binary-tree/)|[Python](./questions/check-completeness-of-a-binary-tree/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|1009|[Complement of Base 10 Integer](https://leetcode.com/problems/complement-of-base-10-integer/)|[Python](./questions/complement-of-base-10-integer/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|1029|[Check If It Is a Straight Line](https://leetcode.com/problems/check-if-it-is-a-straight-line/)|[Python](./questions/check-if-it-is-a-straight-line/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|1035|[Uncrossed Lines](https://leetcode.com/problems/uncrossed-lines/)|[Python](./questions/uncrossed-lines/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|1044|[Longest Duplicate Substring](https://leetcode.com/problems/longest-duplicate-substring/)|[Python](./questions/longest-duplicate-substring/)|![Hard](https://img.shields.io/badge/-Hard-red)|
+|1049|[Last Stone Weight II](https://leetcode.com/problems/last-stone-weight-ii/)|[Python](./questions/last-stone-weight-ii/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|1071|[Greatest Common Divisor of Strings](https://leetcode.com/problems/greatest-common-divisor-of-strings/)|[Python](./questions/greatest-common-divisor-of-strings/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|1081|[Smallest Subsequence of Distinct Characters](https://leetcode.com/problems/smallest-subsequence-of-distinct-characters/)|[Python](./questions/smallest-subsequence-of-distinct-characters/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|1143|[Longest Common Subsequence](https://leetcode.com/problems/longest-common-subsequence/)|[Python](./questions/longest-common-subsequence/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|1232|[Check If It Is a Straight Line](https://leetcode.com/problems/check-if-it-is-a-straight-line/)|[Python](./questions/check-if-it-is-a-straight-line/)|![Easy](https://img.shields.io/badge/-Easy-green)|
+|1277|[Count Square Submatrices with All Ones](https://leetcode.com/problems/count-square-submatrices-with-all-ones/)|[Python](./questions/count-square-submatrices-with-all-ones/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|1288|[Remove Covered Intervals](https://leetcode.com/problems/remove-covered-intervals/)|[Python](./questions/remove-covered-intervals/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
+|1344|[Angle Between Hands of a Clock](https://leetcode.com/problems/angle-between-hands-of-a-clock/)|[Python](./questions/angle-between-hands-of-a-clock/)|![Medium](https://img.shields.io/badge/-Medium-orange)|
 
 ### Features
 
@@ -354,12 +354,10 @@ Clone it. Have a look at the solutions or some particular question and get inpir
 You can choose any problem in LeetCode and bring your solution here. However, notice the folder structure of current repo
 
 ```
---algorithms         # contains solutions for algorithmic problems in LeetCode
-  --3sum             # named after the question itself
+--questions          # root folder for questions
+  --3sum             # named after the question title slug
     --Solution.java  # actual code for the solution. the problem description and maybe even explanation
                      #   for the solution are in the form of comments
---shell              # solutions for shell related problems
---databases          # solutions for database related problems
 ```
 
 1. Fork the repository.
diff --git a/download_solutions.py b/download_solutions.py
new file mode 100644
index 0000000..54899f8
--- /dev/null
+++ b/download_solutions.py
@@ -0,0 +1,145 @@
+#!/usr/bin/env python
+"""download solutions from leetcode account
+"""
+import os
+from os import path
+import re
+
+import requests
+from bs4 import BeautifulSoup
+
+
+extension_mapping = {
+    'cpp': 'cpp',
+    'python': 'py',
+    'python3': 'py',
+    'java': 'java',
+    'sql': 'sql',
+    'shell': 'sh',
+}
+comment_mapping = {
+    'cpp': ['/*', '*/'],
+    'python': ['"""', '"""'],
+    'python3': ['"""', '"""'],
+    'java': ['/*', '*/'],
+    'sql': ['/*', '*/'],
+    'shell': [": '", "'"],
+}
+cookie = ''
+
+
+def get_question_meta(session):
+    res = session.get('https://leetcode.com/api/problems/all/')
+    total = res.json()['stat_status_pairs']
+    return [stat for stat in total if stat.get('status') == 'ac' and not stat.get('paid')]
+
+
+def get_question(session, question_meta):
+    res = session.post('https://leetcode.com/graphql', json={
+        "operationName": "questionData",
+        "variables": {
+            "titleSlug": question_meta['stat']['question__title_slug']
+        },
+        "query": "query questionData($titleSlug: String!) {\n  question(titleSlug: $titleSlug) {\n    questionId\n    questionFrontendId\n    boundTopicId\n    title\n    titleSlug\n    content\n    translatedTitle\n    translatedContent\n    isPaidOnly\n    difficulty\n    likes\n    dislikes\n    isLiked\n    similarQuestions\n    exampleTestcases\n    contributors {\n      username\n      profileUrl\n      avatarUrl\n      __typename\n    }\n    topicTags {\n      name\n      slug\n      translatedName\n      __typename\n    }\n    companyTagStats\n    codeSnippets {\n      lang\n      langSlug\n      code\n      __typename\n    }\n    stats\n    hints\n    solution {\n      id\n      canSeeDetail\n      paidOnly\n      hasVideoSolution\n      paidOnlyVideo\n      __typename\n    }\n    status\n    sampleTestCase\n    metaData\n    judgerAvailable\n    judgeType\n    mysqlSchemas\n    enableRunCode\n    enableTestMode\n    enableDebugger\n    envInfo\n    libraryUrl\n    adminUrl\n    __typename\n  }\n}\n",
+    })
+    content = res.json()['data']['question']['content']
+    question = '<html>{}</html>'.format(content)
+    soup = BeautifulSoup(question, features="html.parser")
+    return soup.get_text()
+
+
+def get_solution(session, question_meta):
+    res = session.post('https://leetcode.com/graphql', json={
+        "operationName": "Submissions",
+        "variables": {
+            "offset": 0,
+            "limit": 20,
+            "lastKey": None,
+            "questionSlug": question_meta['stat']['question__title_slug']
+        },
+        "query": "query Submissions($offset: Int!, $limit: Int!, $lastKey: String, $questionSlug: String!) {\n  submissionList(offset: $offset, limit: $limit, lastKey: $lastKey, questionSlug: $questionSlug) {\n    lastKey\n    hasNext\n    submissions {\n      id\n      statusDisplay\n      lang\n      runtime\n      timestamp\n      url\n      isPending\n      memory\n      __typename\n    }\n    __typename\n  }\n}\n"
+    })
+    submissions = res.json()['data']['submissionList']['submissions']
+    selected = None
+    lang = None
+    for submission in submissions:
+        lang = submission['lang']
+        status = submission['statusDisplay']
+        if status == 'Accepted':
+            selected = submission
+            break
+    if selected is None:
+        return None
+    res = session.get('https://leetcode.com{}'.format(selected['url']))
+    code_line = ''
+    for line in res.text.split('\n'):
+        if 'submissionCode:' in line:
+            code_line = line
+            break
+    match = re.search("submissionCode: '(.+)'", code_line)
+    if match is None:
+        print('cannot find solution: ', question_meta['stat']['question__title'])
+        return None, None
+    code_line = match.group(1)
+    code_line = code_line.encode('utf-8').decode('unicode-escape')
+    return code_line, lang
+
+
+def solution_exists(question_meta, lang):
+    if lang not in extension_mapping:
+        print('unknown lang', lang)
+        return True
+    title = question_meta['stat']['question__title']
+    title_slug = question_meta['stat']['question__title_slug']
+    link = 'https://leetcode.com/problems/{}/'.format(title_slug)
+    # difficulty = question_meta['stat']['difficulty']['level']
+    target_dir = './questions/{}/'.format(title_slug)
+    if not path.exists(target_dir):
+        os.makedirs(target_dir)
+    else:
+        return True
+    filepath = '{}{}.{}'.format(target_dir, 'Solution', extension_mapping[lang])
+    if path.exists(filepath):
+        return True
+    return False
+
+
+def output_solution(question_meta, question, solution, lang):
+    title_slug = question_meta['stat']['question__title_slug']
+    target_dir = './questions/{}/'.format(title_slug)
+    filepath = '{}{}.{}'.format(target_dir, 'Solution', extension_mapping[lang])
+    opening, closing = comment_mapping[lang]
+    with open(filepath, 'w') as ofile:
+        ofile.write(opening + '\n')
+        ofile.write('\n')
+        ofile.write(question)
+        ofile.write('\n')
+        ofile.write(closing + '\n')
+        ofile.write('\n\n')
+        ofile.write(solution)
+    return True
+    
+
+
+def main():
+    with requests.Session() as session:
+        session.headers.update({'Cookie': cookie})
+        question_metas = get_question_meta(session)
+        for question_meta in question_metas:
+            if solution_exists(question_meta, 'python'):
+                continue
+            question = get_question(session, question_meta)
+            solution, lang = get_solution(session, question_meta)
+            if solution is None:
+                continue
+            outputed = output_solution(question_meta, question, solution, lang)
+            title = question_meta['stat']['question__title']
+            if not outputed:
+                print('ignore:', title)
+            else:
+                print('output:', title)
+
+
+
+if __name__ == '__main__':
+    main()
diff --git a/algorithms/1-bit-and-2-bit-characters/Solution.py b/questions/1-bit-and-2-bit-characters/Solution.py
similarity index 100%
rename from algorithms/1-bit-and-2-bit-characters/Solution.py
rename to questions/1-bit-and-2-bit-characters/Solution.py
diff --git a/algorithms/3sum-closest/Solution.java b/questions/3sum-closest/Solution.java
similarity index 100%
rename from algorithms/3sum-closest/Solution.java
rename to questions/3sum-closest/Solution.java
diff --git a/algorithms/3sum/Solution.java b/questions/3sum/Solution.java
similarity index 100%
rename from algorithms/3sum/Solution.java
rename to questions/3sum/Solution.java
diff --git a/algorithms/3sum/Solution.py b/questions/3sum/Solution.py
similarity index 100%
rename from algorithms/3sum/Solution.py
rename to questions/3sum/Solution.py
diff --git a/algorithms/add-and-search-word-data-structure-design/Solution.py b/questions/add-and-search-word-data-structure-design/Solution.py
similarity index 100%
rename from algorithms/add-and-search-word-data-structure-design/Solution.py
rename to questions/add-and-search-word-data-structure-design/Solution.py
diff --git a/algorithms/add-binary/Solution.java b/questions/add-binary/Solution.java
similarity index 100%
rename from algorithms/add-binary/Solution.java
rename to questions/add-binary/Solution.java
diff --git a/algorithms/add-digits/Solution.cpp b/questions/add-digits/Solution.cpp
similarity index 100%
rename from algorithms/add-digits/Solution.cpp
rename to questions/add-digits/Solution.cpp
diff --git a/algorithms/add-two-numbers-ii/Solution.py b/questions/add-two-numbers-ii/Solution.py
similarity index 100%
rename from algorithms/add-two-numbers-ii/Solution.py
rename to questions/add-two-numbers-ii/Solution.py
diff --git a/algorithms/add-two-numbers/Solution.java b/questions/add-two-numbers/Solution.java
similarity index 100%
rename from algorithms/add-two-numbers/Solution.java
rename to questions/add-two-numbers/Solution.java
diff --git a/algorithms/add-two-numbers/Solution.py b/questions/add-two-numbers/Solution.py
similarity index 100%
rename from algorithms/add-two-numbers/Solution.py
rename to questions/add-two-numbers/Solution.py
diff --git a/algorithms/all-possible-full-binary-trees/Solution.py b/questions/all-possible-full-binary-trees/Solution.py
similarity index 100%
rename from algorithms/all-possible-full-binary-trees/Solution.py
rename to questions/all-possible-full-binary-trees/Solution.py
diff --git a/algorithms/angle-between-hands-of-a-clock/Solution.py b/questions/angle-between-hands-of-a-clock/Solution.py
similarity index 100%
rename from algorithms/angle-between-hands-of-a-clock/Solution.py
rename to questions/angle-between-hands-of-a-clock/Solution.py
diff --git a/algorithms/array-partition-i/Solution.py b/questions/array-partition-i/Solution.py
similarity index 100%
rename from algorithms/array-partition-i/Solution.py
rename to questions/array-partition-i/Solution.py
diff --git a/algorithms/backspace-string-compare/Solution.py b/questions/backspace-string-compare/Solution.py
similarity index 100%
rename from algorithms/backspace-string-compare/Solution.py
rename to questions/backspace-string-compare/Solution.py
diff --git a/algorithms/balanced-binary-tree/Solution.java b/questions/balanced-binary-tree/Solution.java
similarity index 100%
rename from algorithms/balanced-binary-tree/Solution.java
rename to questions/balanced-binary-tree/Solution.java
diff --git a/algorithms/baseball-game/Solution.py b/questions/baseball-game/Solution.py
similarity index 100%
rename from algorithms/baseball-game/Solution.py
rename to questions/baseball-game/Solution.py
diff --git a/algorithms/basic-calculator-ii/Solution.py b/questions/basic-calculator-ii/Solution.py
similarity index 100%
rename from algorithms/basic-calculator-ii/Solution.py
rename to questions/basic-calculator-ii/Solution.py
diff --git a/algorithms/best-time-to-buy-and-sell-stock-iv/Solution.py b/questions/best-time-to-buy-and-sell-stock-iv/Solution.py
similarity index 100%
rename from algorithms/best-time-to-buy-and-sell-stock-iv/Solution.py
rename to questions/best-time-to-buy-and-sell-stock-iv/Solution.py
diff --git a/algorithms/best-time-to-buy-and-sell-stock/Solution.py b/questions/best-time-to-buy-and-sell-stock/Solution.py
similarity index 100%
rename from algorithms/best-time-to-buy-and-sell-stock/Solution.py
rename to questions/best-time-to-buy-and-sell-stock/Solution.py
diff --git a/databases/big-countries/Solution.sql b/questions/big-countries/Solution.sql
similarity index 100%
rename from databases/big-countries/Solution.sql
rename to questions/big-countries/Solution.sql
diff --git a/algorithms/binary-gap/Solution.py b/questions/binary-gap/Solution.py
similarity index 100%
rename from algorithms/binary-gap/Solution.py
rename to questions/binary-gap/Solution.py
diff --git a/algorithms/binary-number-with-alternating-bits/Solution.py b/questions/binary-number-with-alternating-bits/Solution.py
similarity index 100%
rename from algorithms/binary-number-with-alternating-bits/Solution.py
rename to questions/binary-number-with-alternating-bits/Solution.py
diff --git a/algorithms/binary-search-tree-iterator/Solution.py b/questions/binary-search-tree-iterator/Solution.py
similarity index 100%
rename from algorithms/binary-search-tree-iterator/Solution.py
rename to questions/binary-search-tree-iterator/Solution.py
diff --git a/algorithms/binary-search/Solution.py b/questions/binary-search/Solution.py
similarity index 100%
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