Given an image represented by an NxN matrix, where each pixel in the image is
4 bytes, write a method to rotate the image by 90 degrees. Can you do this in
place?
将matrix切成4份即可
1 public static void imageRotation(int[][] matrix, int n) { 2 for (int i = 0; i < n / 2; i++) { 3 for (int j = i; j < n - 1 - i; j++) { 4 int tmp = matrix[i][j]; 5 matrix[i][j] = matrix[n - 1 - j][i]; 6 matrix[n - 1 - j][i] = matrix[n - 1 - i][n - 1 - j]; 7 matrix[n - 1 - i][n - 1 - j] = matrix[j][n - 1 - i]; 8 matrix[j][n - 1 - i] = tmp; 9 } 10 } 11 }
原文：http://www.cnblogs.com/superbo/p/4112640.html