leetcode59. 螺旋矩阵 II

和遍历一样设置四个边界按顺序一层层的生成

def generateMatrix(self, n):
        """
        :type n: int
        :rtype: List[List[int]]
        """
        matrix = [[0]*n for i in range(n)]
        count = 1
        l,r = 0,len(matrix[0])-1
        t,b = 0,len(matrix)-1
        while count <= n*n:
            for i in range(l,r+1):
                matrix[t][i] = count
                count += 1
            t += 1
            for i in range(t,b+1):
                matrix[i][r] = count
                count += 1
            r -= 1
            for i in range(r,l-1,-1):
                matrix[b][i] = count
                count += 1
            b -= 1
            for i in range(b,t-1,-1):
                matrix[i][l] = count
                count += 1
            l += 1
        return matrix
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27