Rotate Image

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?

Solution

class Solution(object):
    def rotate(self, matrix):
        """
        :type matrix: List[List[int]]
        :rtype: void Do not return anything, modify matrix in-place instead.
        """
        n = len(matrix)

        for i in range(n):
            for j in range(n - i):
                matrix[i][j], matrix[n-1-j][n-1-i] = matrix[n-1-j][n-1-i], matrix[i][j]

        for i in range(n/2):
            for j in range(n):
                matrix[i][j], matrix[n - 1 - i][j] = matrix[n - 1 - i][j], matrix[i][j]