Tracer Deployment UVALive - 8271 二分图匹配

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <cstring>
#include <vector>
#include <string>
#include <queue>
#include <map>
#include <set>

#define FRER() freopen("in.txt", "r", stdin);
#define INF 0x3f3f3f3f

using namespace std;

const int MAXN = 25;
int n, m, k;
int g[MAXN][MAXN], num[MAXN];
bool vis[MAXN];

bool find(int);
int hungury();

int main()
{
    //FRER()
    ios::sync_with_stdio(0);
    cin.tie(0);
    int u, v;
    while(cin >> n && n) {
        cin >> m >> k;
        memset(g, 0, sizeof(g));
        while(k--) {
            cin >> u >> v;
            g[u][v] = 1;
        }
        cout << hungury() << endl;
    }
    return 0;
}

bool find(int u) {
    for(int v = 0; v < m; ++v) {
        if(g[u][v] && !vis[v]) {
            vis[v] = true;  //标记该点在本次匹配中已被尝试修改过
            if(num[v] == -1 || find(num[v])) {
                num[v] = u;
                return true;
            }
        }
    }
    return false;
}

int hungury() {
    int ans = 0;
    memset(num, -1, sizeof(num));
    for(int i = 0; i < n; ++i) {
        memset(vis, false, sizeof(vis));
        if(find(i)) ++ans;
    }
    return ans;
}