# You are given an n x n 2D matrix representing an image.

# Rotate the image by 90 degrees (clockwise).

# Note:

# You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the rotation.

# Example 1:

# Given input matrix =
# [
#   [1,2,3],
#   [4,5,6],
#   [7,8,9]
# ],

# rotate the input matrix in-place such that it becomes:
# [
#   [7,4,1],
#   [8,5,2],
#   [9,6,3]
# ]
# Example 2:

# Given input matrix =
# [
#   [ 5, 1, 9,11],
#   [ 2, 4, 8,10],
#   [13, 3, 6, 7],
#   [15,14,12,16]
# ],

# rotate the input matrix in-place such that it becomes:
# [
#   [15,13, 2, 5],
#   [14, 3, 4, 1],
#   [12, 6, 8, 9],
#   [16, 7,10,11]
# ]


class Solution:
    # score:99.46(36ms)
    # time:O(n^2)
    # space:O(1)
    def rotate(self, matrix):
        """
        :type matrix: List[List[int]]
        :rtype: void Do not return anything, modify matrix in-place instead.
        """
        # Turn upside down
        for l, r in zip(range(len(matrix)), range(len(matrix)-1, 0, -1)):
            if l >= r:
                break
            matrix[l], matrix[r] = matrix[r], matrix[l]

        # Swap symmetry
        for i in range(len(matrix)):
            for j in range(i+1, len(matrix)):
                matrix[i][j], matrix[j][i] = matrix[j][i], matrix[i][j]
