From 5756b5e1142613686e54480db363cc4a6da0fc52 Mon Sep 17 00:00:00 2001
From: Ashish Kumar Rastogi <83218800+Ashishr1234@users.noreply.github.com>
Date: Sat, 1 Oct 2022 19:51:28 +0530
Subject: [PATCH] Create Next Permutation algo

---
 Next Permutation algo | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 Next Permutation algo

diff --git a/Next Permutation algo b/Next Permutation algo
new file mode 100644
index 00000000..59dd2c26
--- /dev/null
+++ b/Next Permutation algo	
@@ -0,0 +1,24 @@
+
+class Solution {
+public:
+    void nextPermutation(vector<int> &num) 
+    {
+        if (num.empty()) return;
+        
+        // in reverse order, find the first number which is in increasing trend (we call it violated number here)
+        int i;
+        for (i = num.size()-2; i >= 0; --i)
+        {
+            if (num[i] < num[i+1]) break;
+        }
+        
+        // reverse all the numbers after violated number
+        reverse(begin(num)+i+1, end(num));
+        // if violated number not found, because we have reversed the whole array, then we are done!
+        if (i == -1) return;
+        // else binary search find the first number larger than the violated number
+        auto itr = upper_bound(begin(num)+i+1, end(num), num[i]);
+        // swap them, done!
+        swap(num[i], *itr);
+    }
+};