leetcode-Spiral Matrix II 螺旋矩阵2之python大法好，四行就搞定，你敢信？

Spiral Matrix II

螺旋矩阵

Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.

For example,
Given n = 3,

You should return the following matrix:

[
 [ 1, 2, 3 ],
 [ 8, 9, 4 ],
 [ 7, 6, 5 ]
]

　　真的不容易。。看博客园有人面试碰到过这个问题，长篇大论看得我头晕。跑去leetcode讨论区，看来看去还是我python大法牛逼，四行就搞定了你敢信。。

| 1 | 2 | 3 |

| 8 | 9 | 4 |

| 7   6 | 5 |

如果看不明白的话，大致过程像上面这样，颜色相同表示在同一步骤里面执行

>>> def generateMatrix(n):
...     A, low = [], n*n+1
...     while low > 1:
...         low, high = low - len(A), low
...         A = [list(range(low, high))] + list(zip(*A[::-1]))  # python3.3 语法 与2.7会有差别
...         print(A)
...     return A
...
>>> generateMatrix(1)
[[]]
[[1]]
[[1]]
>>> generateMatrix(2)
[[]]
[[4]]
[[3],
 (4,)]
[[1, 2],
 (4, 3)]
[[1, 2], (4, 3)]
>>> generateMatrix(3)
[[]]
[[9]]
[[8],
 (9,)]
[[6, 7],
 (9, 8)]
[[4, 5],
 (9, 6),
 (8, 7)]
[[1, 2, 3],
 (8, 9, 4),
 (7, 6, 5)]
[[1, 2, 3], (8, 9, 4), (7, 6, 5)]