【特例】73. 矩阵置零

题目

Python

class Solution:
    def setZeroes(self, matrix: List[List[int]]) -> None:
        """
        Do not return anything, modify matrix in-place instead.
        """
        i_set = set()
        j_set = set()
        m = len(matrix)
        n = len(matrix[0])
        for i in range(0, m):
            for j in range(0, n):
                if matrix[i][j] == 0:
                    i_set.add(i)
                    j_set.add(j)

        for i in range(0, m):
            for j in range(0, n):
                if i in i_set or j in j_set:
                    matrix[i][j] = 0

Java

法1：自己想的笨蛋方法

class Solution {
    public void setZeroes(int[][] matrix) {
        Set<Integer> rowSet = new HashSet<>();
        Set<Integer> columnSet = new HashSet<>();
        for (int i = 0; i < matrix.length; ++i) {
            for (int j = 0; j < matrix[0].length; ++j) {
                if (matrix[i][j] == 0) {
                    rowSet.add(i);
                    columnSet.add(j);
                }
            }
        }
        for (int i = 0; i < matrix.length; ++i) {
            if (rowSet.contains(i)) {
                Arrays.fill(matrix[i], 0);
            }
        }
        for (int j = 0; j < matrix[0].length; ++j) {
            if (columnSet.contains(j)) {
                for (int i = 0; i < matrix.length; ++i) {
                    matrix[i][j] = 0;
                }
            }
        }
    }
}

// 代码优雅版
class Solution {
    public void setZeroes(int[][] matrix) {
        int m = matrix.length, n = matrix[0].length;
        boolean[] row = new boolean[m];
        boolean[] col = new boolean[n];
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                if (matrix[i][j] == 0) {
                    row[i] = col[j] = true;
                }
            }
        }
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                if (row[i] || col[j]) {
                    matrix[i][j] = 0;
                }
            }
        }
    }
}

作者：力扣官方题解
链接：https://leetcode.cn/problems/set-matrix-zeroes/solutions/669901/ju-zhen-zhi-ling-by-leetcode-solution-9ll7/
来源：力扣（LeetCode）
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法2：

放个链接，估计真遇到了也写不出来。。。
https://leetcode.cn/problems/set-matrix-zeroes/solutions/670278/xiang-jie-fen-san-bu-de-o1-kong-jian-jie-dbxd/?envType=study-plan-v2&envId=top-100-liked