Question
Solution
把这个二维数组(矩阵)看成一个一个环，循环每个环，循环每条边，每个边上的点进行旋转
public void rotate(int[][] matrix) {
int n = matrix.length;
for (int i = 0; i < n / 2; i++) {
change(matrix, i);
}
}
private void change(int[][] matrix, int i) {
int n = matrix.length - 1;
for (int j = i; j < n - i; j++) {
int tmp = matrix[i][j];
matrix[i][j] = matrix[n - j][i];
matrix[n - j][i] = matrix[n - i][n - j];
matrix[n - i][n - j] = matrix[j][n - i];
matrix[j][n - i] = tmp;
}
}