【LeetCode with Python】 Spiral Matrix II

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原题页面： https://oj.leetcode.com/problems/spiral-matrix-ii/
题目类型：
难度评价：★
本文地址： http://blog.csdn.net/nerv3x3/article/details/41628823

Given an integer n, generate a square matrix filled with elements from 1 ton² in spiral order.

For example,
Given n = 3,

You should return the following matrix:

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

评论

class Solution:
    # @return a list of lists of integer
    def generateMatrix(self, n):

        if 0 == n:
            return [ ]
        m = n
        index = 1
        matrix = [[0 for x in range(0, n)] for y in range(0, n)]
        round = (n + 1) / 2
        for x in range(0, round):
            for y in range(x, n - x):
                matrix[x][y] = index
                index += 1
            for y in range(x + 1, m - x - 1):
                matrix[y][n - x - 1] = index
                index += 1
            if m - 2 * x > 1:  ###
                for y in range(n - x - 1, x - 1, -1):
                    matrix[m - x - 1][y] = index
                    index += 1
            if n - 2 * x > 1:      ###
                for y in range(m - x - 2, x, -1):   ###
                    matrix[y][x] = index
                    index += 1
        return matrix