旋转二维数组90度

题目

You are given an n x n 2D matrix representing an image.
Rotate the image by 90 degrees (clockwise).
Follow up:
Could you do this in-place?

java实现

public void rotate(int[][] matrix) {
        int row = matrix.length;
        int col = matrix[0].length;
        int[][] copy = new int[row][col];
        for (int i = 0; i < row; i++) {
            for (int j = 0; j < col; j++) {
                copy[j][row - 1 - i] = matrix[i][j];
            }
        }
        for (int i = 0; i < row; i++) {
            for (int j = 0; j < col; j++) {
                matrix[i][j] = copy[i][j];
            }
        }
    }