leetcood学习笔记-59-螺旋矩阵二

题目描述：

参考后的提交：

class Solution:

    def generateMatrix(self, n: int):

        #l = [[0] * n] * n  此创建方法错误

        l = [[] for i in range(n)]

        for i in range(n):

            for j in range(n):

                l[i].append(0)##l=[[o for i in range(n)]for i in range[n]]

        #print(l)

        j,m = 0,1

        while m<=n*n:

            for i in range(j,n-j):

                l[j][i] = m

                m += 1

            for i in range(j+1,n-j):

                l[i][n-j-1] = m

                m += 1

            for i in range(n-j-2,j-1,-1):

                l[n-j-1][i] = m

                m += 1

            for i in range(n-j-2,j,-1):

                l[i][j] = m

                m += 1

            j += 1

        return l

注意：

l = [[0]*3]*3用这种方法生成二维列表时 改变其中一值，其它列相对应值改变！也就是说matrix = [array] * 3操作中，只是创建3个指向array的引用，所以一旦array改变，matrix中3个list也会随之改变。

创建二维数组的方法：matrix = [[0 for i in range(3)] for i in range(3)]

其他：

class Solution(object):

    def generateMatrix(self, n):

        """

        :type n: int

        :rtype: List[List[int]]

        """

        res = [[0 for __ in range(n)] for _ in range(n)]

        up,down,left,right = 0,n,0,n  #上下左右边界

        index = 1

        while  index <= n**2:

            for i in range(left,right):  #向右

                res[up][i] = index

                index += 1

            up += 1

            for i in range(up,down):     #向下

                res[i][right-1] = index

                index += 1

            right -= 1

            for i in range(right-1,left-1,-1):  #向左

                res[down-1][i] = index

                index += 1

            down -= 1

            for i in range(down-1,up-1,-1):  #向上

                res[i][left] = index

                index += 1

            left += 1

        return res

巴特西

leetcood学习笔记-59-螺旋矩阵二

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