73. matrix zeroing (marking method)

subject ： Matrix zeroing Given a m x n Matrix , If an element is 0 , Set all elements of the row and column to 0 . Please use In situ Algorithm .

Ideas ： First, set the row marked by the two arrays , Which column is promising 0 The elements of , Then traverse the matrix , Mark the qualified ones as 0 that will do .

code

class Solution {
public:
    void setZeroes(vector<vector<int>>& matrix) {
        int m = matrix.size();
        int n = matrix[0].size();
        vector<int> row(m), col(n);
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                if (!matrix[i][j]) {
                    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;
                }
            }
        }
    }
};

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