正方形矩阵 顺时针旋转90度

package my_basic.class_3;

/*正方形矩阵 顺时针旋转矩阵 90度*/
public class Code_06_RotateMatrix {
    
    public static void rotate(int[][] matrix) {
        int tr = 0;
        int tc = 0;
        int dr = matrix.length-1;
        int dc = matrix[0].length-1;
        while(tr < dr) {
            rotateEdge(matrix,tr++,tc++,dr--,dc--); /*从外圈  到里圈*/
        }
    }

    public static void rotateEdge(int[][] matrix, int tr, int tc, int dr, int dc) {
        int times = dc - tc; 
        int tmp = 0;
        for(int i=0; i!=times;i++) {
            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;
        }
    }
    public static void printMatrix(int[][] matrix) {
        for (int i = 0; i < matrix.length; i++) {
            for(int j = 0; j < matrix[0].length;j++) {
                System.out.print(matrix[i][j] + " ");
            }
            System.out.println();
        }
    }
    
    public static void main(String[] args) {
        int[][] matrix = { { 1, 2, 3, 4 }, { 5, 6, 7, 8 }, { 9, 10, 11, 12 },
                { 13, 14, 15, 16 } };
        printMatrix(matrix);
        System.out.println("===============");
        rotate(matrix);
        printMatrix(matrix);
    }
}