Rotate Image

def rotate(self, matrix):
    """
    :type matrix: List[List[int]]
    :rtype: None Do not return anything, modify matrix in-place instead.
    """
    n = len(matrix)
    for i in range(n/2):
        for j in range(n-n/2):
            matrix[i][j], matrix[~j][i], matrix[~i][~j], matrix[j][~i] = \
                     matrix[~j][i], matrix[~i][~j], matrix[j][~i], matrix[i][j]