Rotate Image
Medium
Array
Math
Matrix
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]]

Constraints

  • •n == matrix.length == matrix[i].length
  • •1 <= n <= 20
  • •-1000 <= matrix[i][j] <= 1000
Time Complexity
O(n²)
Space Complexity
O(1)
14
Case 1
Input: [[1,2,3],[4,5,6],[7,8,9]]
Expected: [[7,4,1],[8,5,2],[9,6,3]]
Case 2
Input: [[5,1,9,11],[2,4,8,10],[13,3,6,7],[15,14,12,16]]
Expected: [[15,13,2,5],[14,3,4,1],[12,6,8,9],[16,7,10,11]]
Case 3
Input: [[1]]
Expected: [[1]]