22.Rotate Image-旋转图像

解析：循环 交换 先旋转最外层，再依次向里

class Solution {
    public void rotate(int[][] matrix) {
        int tR = 0, tC = 0;  //矩阵的左上角元素的坐标
        int dR = matrix.length - 1, dC = matrix[0].length - 1;  //矩阵右下角元素的坐标
        while (tR <= dR) {
            int times = dC - tC; //需要循环的次数
            for (int i = 0; i < times; i++) {
                int tmp = matrix[tR][tC + i];
                matrix[tR][tC + i] = matrix[dR - i][tC];
                matrix[dR - i][tC] = matrix[dR][dC - i];
                matrix[dR][dC - i] = matrix[tR+i][dC];
                matrix[tR+i][dC] = tmp;
            }
            tR++;
            tC++;
            dR--;
            dC--;
        }
    }
}