顺时针旋转90度等于先转置再左右翻转

顺时针旋转180度等于先上下翻转再左右翻转

顺时针旋转270度等于先左右翻转再转置

package leetcode;

public class demo_48 {
    public void rotate(int[][] matrix) {
        //顺时针旋转90度等于先转置再对称翻转
        for(int i=0;i<matrix.length;i++) {
            for(int j=i+1;j<matrix.length;j++) {
                int t=matrix[i][j];
                matrix[i][j]=matrix[j][i];
                matrix[j][i]=t;
            }
        }
        for(int i=0;i<matrix.length;i++) {
            for(int j=0;j<matrix.length/2;j++) {
                int t=matrix[i][j];
                matrix[i][j]=matrix[i][matrix.length-1-j];
                matrix[i][matrix.length-1-j]=t;
            }
        }
        for(int[] s:matrix) {
            for(int i:s) {
                System.out.print(i+" ");
            }
        }
    }
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        demo_48 d48=new demo_48();
        int[][]matrix= {{1,2,3},{4,5,6},{7,8,9}};
        d48.rotate(matrix);
    }
}