标签：class blog code java 2014 for
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?
public class Solution {
/**The algorithm is simple.
* @author Averill Zheng
* @version 2014-06-15
* @since JDK 1.7
*/
public void rotate(int[][] matrix) {
int length = matrix.length;
for(int i = 0; i < length / 2; ++i){
for(int k = i; k < length - 1 - i; ++k){
matrix[i][k] += (matrix[k][length - 1 - i] + matrix[length - 1 - i][length - 1 - k]
+ matrix[length - 1 - k][i]);
matrix[k][length - 1 - i] = (matrix[i][k] - matrix[k][length - 1 - i]
- matrix[length - 1 - i][length - 1 - k]
- matrix[length - 1 - k][i]);
matrix[length - 1 - i][length - 1 - k] = (matrix[i][k] - matrix[k][length - 1 - i]
- matrix[length - 1 - i][length - 1 - k]
- matrix[length - 1 - k][i]);
matrix[length - 1 - k][i] = (matrix[i][k] - matrix[k][length - 1 - i]
- matrix[length - 1 - i][length - 1 - k]
- matrix[length - 1 - k][i]);
matrix[i][k] = (matrix[i][k] - matrix[k][length - 1 - i]
- matrix[length - 1 - i][length - 1 - k]
- matrix[length - 1 - k][i]);
}
}
}
}
leetcode--Rotate Image,布布扣,bubuko.com
标签：class blog code java 2014 for
原文地址：http://www.cnblogs.com/averillzheng/p/3790273.html
