[LeetCode]Rotate Image@python@python

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]
]

解法一：解题思路：先将矩阵转置，然后将矩阵的每一行翻转，就可以得到所要求的矩阵了。（注意学会转置矩阵的写法！）

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(i+1, n):
matrix[i][j], matrix[j][i] = matrix[j][i], matrix[i][j]
for i in range(n):
matrix[i].reverse()

解法二：用python独有的zip方法（只要一行，好好理解这个方法的写法，特别是map的作用）

matrix[::] = map(list,zip(*matrix[::-1]))