rotate matrix

Author: sachuverma

Striver Sheet/Day-2/Rotate Image.cpp

@@ -0,0 +1,65 @@
+/*
+Rotate Image
+============
+
+You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise).
+
+You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the rotation.
+
+Example 1:
+Input: matrix = [[1,2,3],[4,5,6],[7,8,9]]
+Output: [[7,4,1],[8,5,2],[9,6,3]]
+
+Example 2:
+Input: matrix = [[5,1,9,11],[2,4,8,10],[13,3,6,7],[15,14,12,16]]
+Output: [[15,13,2,5],[14,3,4,1],[12,6,8,9],[16,7,10,11]]
+
+Example 3:
+Input: matrix = [[1]]
+Output: [[1]]
+
+Example 4:
+Input: matrix = [[1,2],[3,4]]
+Output: [[3,1],[4,2]]
+
+Constraints:
+matrix.length == n
+matrix[i].length == n
+1 <= n <= 20
+-1000 <= matrix[i][j] <= 1000
+*/
+
+class Solution
+{
+public:
+  void rotate(vector<vector<int>> &matrix)
+  {
+    int n = matrix.size();
+    if (!n)
+      return;
+    int m = matrix[0].size();
+    if (!m)
+      return;
+
+    for (int i = 0; i < n; ++i)
+    {
+      for (int j = 0; j < i; ++j)
+      {
+        int temp = matrix[i][j];
+        matrix[i][j] = matrix[j][i];
+        matrix[j][i] = temp;
+      }
+    }
+
+    for (int i = 0; i < n; ++i)
+    {
+      int mi = 0, ma = m - 1;
+      while (mi < ma)
+      {
+        swap(matrix[i][mi], matrix[i][ma]);
+        mi++;
+        ma--;
+      }
+    }
+  }
+};

Striver Sheet/README.md

@@ -1,5 +1,7 @@
 # STRIVER DSA SHEET
 
+[Sheet Link](https://docs.google.com/document/d/1JLKCaz4n4YtYdQ1bJF1X46BKbxldedb6N1OMiXh9Dmo/edit?usp=sharing)
+
 ### Day 1 (Arrays)
 
 - [Sort an array of 0’s 1’s 2’s without using extra space or sorting algo](https://leetcode.com/problems/sort-colors/) - [Cpp Soultion](./Day-1/Sort%20Colors.cpp)
@@ -16,7 +18,7 @@
 - [Next Permutation](https://leetcode.com/problems/next-permutation/) - [Cpp Soultion](./Day-2/Next%20Permutation.cpp)
 - [Count Inversions in an array](https://www.geeksforgeeks.org/counting-inversions/) - [Cpp Soultion](./Day-2/Count%20Inversions.cpp)
 - [Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/) - [Cpp Soultion](./Day-2/Best%20Time%20to%20Buy%20and%20Sell%20Stock.cpp)
-- []() - [Cpp Soultion](./Day-2/.cpp)
+- [Rotate Image](https://leetcode.com/problems/rotate-image/) - [Cpp Soultion](./Day-2/Rotate%20Image.cpp)
 
 ###