打卡群刷题总结0713——螺旋矩阵 II

class Solution(object):
    def generateMatrix(self, n):
        """
        :type n: int
        :rtype: List[List[int]]
        """
        num = n * n
        cur = 1
        matrix = [[0] * n for i in range(n)]
        left, right = 0, n - 1
        top, bottom = 0, n - 1
        while top <= bottom and left <= right:
            for j in range(left, right + 1):
                matrix[top][j] = cur
                cur += 1
            top += 1
            for i in range(top, bottom + 1):
                matrix[i][right] = cur
                cur += 1
            right -= 1
            for j in range(right, left - 1, -1):
                matrix[bottom][j] = cur
                cur += 1
            bottom -= 1
            for i in range(bottom, top - 1, -1):
                matrix[i][left] = cur
                cur += 1
            left += 1
        return matrix