LeetCode - Rotate Image (Java)

You are given an n x n 2D matrix representing an image.
Rotate the image by 90 degrees (clockwise).

public void rotate(int[][] matrix) { int n = matrix.length; for (int i = 0; i < n / 2; i++) { for (int j = 0; j < Math.ceil(((double) n) / 2.); j++) { int temp = matrix[i][j]; matrix[i][j] = matrix[n-1-j][i]; matrix[n-1-j][i] = matrix[n-1-i][n-1-j]; matrix[n-1-i][n-1-j] = matrix[j][n-1-i]; matrix[j][n-1-i] = temp; } } }

Also refer to http://blog.csdn.net/kenden23/article/details/17200067

1 原矩阵计算出各个数值在新矩阵中的位置，然后一步到位转换成新的旋转矩阵

2 原矩阵到转置矩阵是很容易计算的，那么从转置矩阵到选择矩阵就只需要reverse每行的元素就可。
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