0048 - Rotate Image

0048 - Rotate Image

GYou 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.

Examples

Input: matrix = [[1,2,3],[4,5,6],[7,8,9]] Output: [[7,4,1],[8,5,2],[9,6,3]]

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]]

Input: matrix = [[1]] Output: [[1]]

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

Java Solution

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