0073. 矩阵置零

[utterances-bot]

0073. 矩阵置零 | 算法通关手册

73. 矩阵置零 # 标签：数组、哈希表、矩阵 难度：中等 题目大意 # 给定一个 m * n 大小的矩阵。 要求：如果一个元素为 0，则将其所在行和列所有元素都置为 0。

https://algo.itcharge.cn/Solutions/0001-0099/set-matrix-zeroes/

[rayjinghaolei]

class Solution:
    def setZeroes(self, matrix: List[List[int]]) -> None:
        m = len(matrix)
        n = len(matrix[0])
        rows = set()
        cols = set()
        for i in range(m):
            for j in range(n):
                if matrix[i][j] == 0:
                    rows.add(i)
                    cols.add(j)
        for i in range(m):
            for j in range(n):
                if i in rows or j in cols:
                    matrix[i][j] = 0

我觉得我这个方法方便一些

[shuaibird]

这个算法空间复杂度就是 O(m + n) 了

[MrGZC]

class Solution:
def setZeroes(self, matrix: List[List[int]]) -> None:
"""
Do not return anything, modify matrix in-place instead.
"""
row, col = len(matrix), len(matrix[0])

    row_list, col_list = [], []

    for i in range(row):
        for j in range(col):
            if matrix[i][j] == 0:
                row_list.append(i)
                col_list.append(j)

    for i in row_list:
        matrix[i] = [0] * col

    for i in col_list:
        for j in range(row):
            matrix[j][i] = 0