leetcode-----73. 矩阵置零

• 链接：https://leetcode-cn.com/problems/set-matrix-zeroes/

代码

class Solution {
public:
    void setZeroes(vector<vector<int>>& matrix) {
        if (matrix.empty() || matrix[0].empty()) return;
        int n = matrix.size(), m = matrix[0].size();

        int r0 = 1, c0 = 1;
        for (int i = 0; i < m; ++i) if (!matrix[0][i]) r0 = 0;
        for (int i = 0; i < n; ++i) if (!matrix[i][0]) c0 = 0;

        for (int i = 1; i < m; ++i) {
            for (int j = 0; j < n; ++j) {
                if (!matrix[j][i]) matrix[0][i] = 0;
            }
        } 
        
        for (int i = 1; i < n; ++i) {
            for (int j = 0; j < m; ++j) {
                if (!matrix[i][j]) matrix[i][0] = 0;
            }
        } 

        for (int i = 1; i < m; ++i) {
            if (!matrix[0][i]) {
                for (int j = 0; j < n; ++j) {
                    matrix[j][i] = 0;
                }
            }
        }

        for (int i = 1; i < n; ++i) {
            if (!matrix[i][0]) {
                for (int j = 0; j < m; ++j) {
                    matrix[i][j] = 0;
                }
            }
        } 

        if (!r0) for (int i = 0; i < m; ++i) matrix[0][i] = 0;
        if (!c0) for (int i = 0; i < n; ++i) matrix[i][0] = 0;
    }
};