rotate-image

packagecom.ytx.array;

/** 题目：rotate-image

 *

 *  描述:     You are given an n x n 2D matrix representing an image.

                    Rotate the image by 90 degrees (clockwise).

                    Follow up:

                    Could you do this in-place?

 *

 *@authoryuantian xin

 *

 *  求将一个n*n的二维矩阵顺时针旋转90度得到的新矩阵

 * 

 *  我是直接找规律,以3*3矩阵为例

 *  matrix[0][0] = matrix[2][0], matrix[0][1] = matrix[1][0], matrix[0][2] = matrix[0][0];

 * 

 *  matrix[1][0] = matrix[2][1], matrix[1][1] = matrix[1][1], matrix[1][2] = matrix[0][1];

 * 

 *  matrix[2][0] = matrix[2][2], matrix[2][1] = matrix[1][2], matrix[2][2] = matrix[0][2];

 * 

 *  得到规律 matrix[i][j] = matrix[len- 1 - j][i]

 *

 */

publicclass Rotate_image {

       

       publicvoid rotate(int[][]matrix) {

       int len = matrix.length;

       int[][]temp = newint[len][len];

       for(inti = 0; i < len;i++) {

             for(intj = 0; j < len;j++) {

                    temp[i][j] = matrix[i][j];

             }

        }

       

       for(inti = 0; i < len;i++) {

             for(intj = 0; j < len;j++) {

                    matrix[i][j] = temp[len- 1 - j][i];

             }

        }

    }

       publicstatic void main(String[]args) {

             int[][]matrix= {{2,3,3},{1,1,1},{3,3,3}};

             newRotate_image().rotate(matrix);

             

             for(inti = 0; i < matrix.length;i++) {

                    for(intj = 0; j < matrix.length;j++) {

                           System.out.print(matrix[i][j] + " ");

                    }

                    System.out.println();

             }

             

       }

}