2188 축사 배정 (이분 매칭)

#include <stdio.h>
#include <vector>
#include <algorithm>
 
using namespace std;
 
vector<vector<int> > adj;
int from[100000] = { 0 };
int visit[100000] = { 0 };
 
int dfs(int x) {
    if (visit[x] == 1) {
    
        return 0;
    }
 
    visit[x] = 1;
    for (int i = 0; i < adj[x].size(); i++) {        
        int tmp = adj[x][i];
 
        if (from[tmp] == 0) {
            from[tmp] = x;
            return 1;
        }
        else {
            if (dfs(from[tmp]) == 1) {
                from[tmp] = x;
                return 1;
            }
        }
    }
    return 0;
}
 
int main() {
    int n, m;
    scanf("%d %d", &n, &m);
 
    adj.resize(n + 1);
    
    for (int i = 1; i <= n; i++) {
        int num;
        scanf("%d", &num);
 
        for (int j = 0; j < num; j++) {
            int tmp;
            scanf("%d", &tmp);
 
            adj[i].push_back(tmp);
        }
    }
 
    int rst = 0;
    for (int i = 1; i <= n; i++) {
        fill(visit, visit + n + 1, 0);
        
        if (dfs(i)==1) 
            rst++;        
    }
    printf("%d", rst);
}