1820. Maximum Number of Accepted Invitations

There are m boys and n girls in a class attending an upcoming party.

You are given an m x n integer matrix grid, where grid[i][j] equals 0 or 1. If grid[i][j] == 1, then that means the ith boy can invite the jth girl to the party. A boy can invite at most one girl, and a girl can accept at most one invitation from a boy.

Return the maximum possible number of accepted invitations.

class Solution {
    bool dfs(int i, vector<vector<int>>& g, vector<int>& matching, vector<bool>& ask) {
        for(int j = 0; j < g[i].size(); j++) {
            if(g[i][j] == 0 or ask[j]) continue;
            ask[j] = true;
            if(matching[j] == -1 or dfs(matching[j],g,matching,ask)) {
                matching[j] = i;
                return true;
            }
        }
        
        
        return false;
    }
public:
    int maximumInvitations(vector<vector<int>>& grid) {
        int n = grid.size(), m = grid[0].size(), res = 0;
        vector<int> matching(m, -1);
        for(int i = 0; i < n; i++)
            res += dfs(i,grid,matching,vector<bool>(m) = {});
        
        return res;
    }
};