07.Rotate Image.java

/*
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]]
 
*/class Solution {
    public void rotate(int[][] matrix) {
        //Transpose of the matrix
        for (int i=0;i<matrix.length;i++){
            for(int j =i;j<matrix[0].length;j++){
                int temp=0;
                temp= matrix[i][j];
                matrix[i][j]=matrix[j][i];
                matrix[j][i]=temp;
            }
        }
        //reverse
        for(int i=0;i<matrix.length;i++){
            for(int j=0;j<matrix.length/2;j++){
                int temp=0;
                temp=matrix[i][j];
                matrix[i][j]=matrix[i][matrix.length-1-j];
                matrix[i][matrix.length-1-j]=temp;
            }
        }
        
    }
}