2024-07-16 01:19:15

Affected files:
.obsidian/workspace.json
src/content/blog/leet-code-919-complete-binary tree-inserter.md

.obsidian/workspace.json

@@ -13,7 +13,7 @@
             "state": {
               "type": "markdown",
               "state": {
-                "file": "src/content/blog/boj-2529-부등호.md",
+                "file": "src/content/blog/leet-code-74-search-a-2d-matrix.md",
                 "mode": "source",
                 "source": false
               }
@@ -22,16 +22,16 @@
         ]
       },
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-        "id": "2b1c3a474105df20",
+        "id": "c93cbacdb763ad00",
         "type": "tabs",
         "children": [
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-            "id": "71e0df042bc7a561",
+            "id": "4077864ed2ae2ddd",
             "type": "leaf",
             "state": {
               "type": "markdown",
               "state": {
-                "file": "src/content/blog/boj-1339-단어-수학.md",
+                "file": "src/content/blog/leet-code-919-complete-binary tree-inserter.md",
                 "mode": "source",
                 "source": false
               }
@@ -103,7 +103,7 @@
             "state": {
               "type": "backlink",
               "state": {
-                "file": "src/content/blog/boj-2529-부등호.md",
+                "file": "src/content/blog/leet-code-919-complete-binary tree-inserter.md",
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                 "extraContext": false,
                 "sortOrder": "alphabetical",
@@ -120,7 +120,7 @@
             "state": {
               "type": "outgoing-link",
               "state": {
-                "file": "src/content/blog/boj-2529-부등호.md",
+                "file": "src/content/blog/leet-code-919-complete-binary tree-inserter.md",
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                 "unlinkedCollapsed": true
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@@ -143,7 +143,7 @@
             "state": {
               "type": "outline",
               "state": {
-                "file": "src/content/blog/boj-2529-부등호.md"
+                "file": "src/content/blog/leet-code-919-complete-binary tree-inserter.md"
               }
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@@ -166,15 +166,16 @@
       "table-editor-obsidian:Advanced Tables Toolbar": false
     }
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-  "active": "bb9e313e9ec35bc3",
+  "active": "4077864ed2ae2ddd",
   "lastOpenFiles": [
-    "src/content/blog/boj-1339-단어-수학.md",
+    "src/content/blog/leet-code-74-search-a-2d-matrix.md",
     "src/content/blog/boj-2529-부등호.md",
+    "src/content/blog/leet-code-919-complete-binary tree-inserter.md",
+    "src/content/blog/boj-1339-단어-수학.md",
     "src/content/blog/boj-2660-회장뽑기.md",
     "src/content/blog/boj-2011-암호코드.md",
     "src/content/blog/leet-code-438-find-all-anagrams-in-a-string.md",
     "src/content/blog/boj-5525-ioioi.md",
-    "src/content/blog/leet-code-74-search-a-2d-matrix.md",
     "src/content/blog/leet-code-1438-longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit.md",
     "src/content/blog/leet-code-64-minimum-path-sum.md",
     "src/content/blog/boj-6593-상범-빌딩.md",
@@ -195,7 +196,6 @@
     "src/content/blog/manage-cli-program-version-using-aqua-proj-on-windows.md",
     "src/content/blog/astro-paper-4.md",
     "src/content/blog/implementing-a-worker-thread-pool-in-c.md",
-    "src/content/blog/boj-5014-스타트링크.md",
     "dist/assets/[email protected]",
     "dist/assets/forrest-gump-quote.webp.jpg",
     "dist/_astro/[email protected]",

src/content/blog/leet-code-919-complete-binary tree-inserter.md

@@ -0,0 +1,92 @@
+---
+author: Gyunseo Lee
+title: "LeetCode 919: Complete Binary Tree Inserter"
+pubDatetime: 2024-07-16T01:16:00+09:00
+modDatetime: 2024-07-16T01:16:00+09:00
+featured: false
+draft: false
+tags:
+  - PS
+  - Algorithms
+  - Binary-Tree-Traversal
+  - Binary-Tree
+  - LeetCode
+  - BFS
+description: 문제를 꼼꼼히 천천히 읽자...
+ogImage: ""
+---
+
+## Table of contents
+
+## 들어가며
+
+걸린 시간: 120분
+
+이 문제를 처음 읽었을 때, binary tree가 아닌 binary search tree로 읽어 버린 실수를 하고 말았습니다.  
+그래서 거의 20분 넘게 삽질을 하다가, complete binary tree라는 것을 깨닫고 다시 처음부터 문제를 접근했습니다.
+
+## 접근
+
+이 문제는 결국 이진 트리를 BFS 방식으로 순회하면 쉽게 해결되는 문제입니다.  
+그런데 뭔가 계속 삽질을 하게 됐습니다.  
+그래서 거의 2시간 걸려서 풀었네요.
+
+## 구현
+
+```python
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
+
+from collections import deque
+
+class CBTInserter:
+    def __init__(self, root: Optional[TreeNode]):
+        self.node_list = [None for _ in range(10000 + 1)]
+        q = deque()
+        q.append((root, 0))
+        self.node_list[0] = root
+        while q:
+            cur_node, cur_idx = q.popleft()
+            next_node_left = cur_node.left
+            next_node_right = cur_node.right
+
+            if next_node_left != None:
+                self.node_list[cur_idx * 2 + 1] = next_node_left
+                q.append((next_node_left, cur_idx * 2 + 1))
+
+
+            if next_node_right != None:
+                self.node_list[cur_idx * 2 + 2] = next_node_right
+                q.append((next_node_right, cur_idx * 2 + 2))
+        # print(self.node_list)
+        self.put_idx = len([*filter(lambda x: x != None, self.node_list)])
+
+    def insert(self, val: int) -> int:
+        # print(self.node_list)
+        self.node_list[self.put_idx] = TreeNode(val)
+
+        # even num (right)
+        if self.put_idx % 2 == 0:
+            parent_idx = self.put_idx // 2 - 1
+            self.node_list[parent_idx].right = self.node_list[self.put_idx]
+        # odd num (left)
+        else:
+            parent_idx = self.put_idx // 2
+            self.node_list[parent_idx].left = self.node_list[self.put_idx]
+
+        self.put_idx += 1
+        return self.node_list[parent_idx].val
+
+    def get_root(self) -> Optional[TreeNode]:
+        return self.node_list[0]
+
+
+# Your CBTInserter object will be instantiated and called as such:
+# obj = CBTInserter(root)
+# param_1 = obj.insert(val)
+# param_2 = obj.get_root()
+```