leetcode (48) rotating the image

Rotate image

Problem-solving ideas: the central symmetry axis of symmetry

class Solution {
    public void rotate(int[][] matrix) {
        int len = matrix.length;
        int temp = 0;
        for(int i=0;i<(len+1)/2;++i){
            for(int j=0;j<len/2;++j){
                temp = matrix[i][j];
                matrix[i][j] = matrix[len-1-j][i];
                matrix[len-1-j][i] = matrix[len-1-i][len-1-j];
                matrix[len-1-i][len-1-j] = matrix[j][len-1-i]; 
                matrix[j][len-1-i] = temp;
            }
        }
    }
}