【leetcode刷题】59 spiral matrix II (python)

原题链接
https://leetcode.com/problems/spiral-matrix-ii
解题思路
用round记录当前处于第几轮，按照上右下左的顺序不断转圈输出即可。但需要注意的是当上下重合为一行时需要判断一下，中止程序。
代码

class Solution(object):
    def generateMatrix(self, n):
        """
        :type n: int
        :rtype: List[List[int]]
        """
        matrix = [[0 for i in range(n)] for j in range(n)]
        round = 0
        index = 1
        # fill the first row
        while round<n//2+1:
            for col in range(round, n-round):
                matrix[round][col] = index
                index += 1
            for row in range(round+1, n-1-round):
                matrix[row][n-1-round] = index
                index += 1
            if n-1-round==round:
                break
            for col in range(n-round-1,round-1,-1):
                matrix[n-1-round][col] = index
                index += 1
            for row in range(n-2-round, round, -1):
                matrix[row][round] = index
                index += 1
            round += 1
        return matrix

参考链接
https://blog.csdn.net/nerv3x3/article/details/41628823