思路
先获取元素为0所在的行和列,用集合rows 存放元素为0的行,集合cols存放元素为0的列
遍历矩阵,遇到的行、列为0元素所在行、列,将对应行、列的元素设置为0
ps:用集合可以去重、用in时时间复杂度O(1)
python">class Solution(object):def setZeroes(self, matrix):""":type matrix: List[List[int]]:rtype: None Do not return anything, modify matrix in-place instead."""rows=set()cols=set()for i in range(len(matrix)):for j in range(len(matrix[i])):if matrix[i][j]==0:rows.add(i)cols.add(j)for i in range(len(matrix)):for j in range(len(matrix[i])):if i in rows:matrix[i][j]=0else:if j in cols:matrix[i][j]=0return matrix