hdu2063 最大匹配数（匈牙利算法）

[code]#include <cstdio>
#include <iostream>
#include <algorithm>
#include <queue>
#include <cmath>
#include <cstring>
#include <stack>
#include <set>
#include <map>
#include <vector>

using namespace std;
#define INF 0x2fffffff
#define LL long long
#define MAX(a,b) ((a)>(b))?(a):(b)
#define MIN(a,b) ((a)<(b))?(a):(b)
int k,n,m;
vector<int> vec[1005];
int vx[1005];
int vy[1005];
int vis[1005];

int path(int u){
    int si = vec[u].size();
    for(int i = 0;i < si;i++){
        int v = vec[u][i];
        if(!vis[v]){
            vis[v] = 1;
            if(vy[v] == -1 || path(vy[v])){
                vx[u] = v;
                vy[v] = u;
                return 1;
            }
        }
    }
    return 0;
}
int maxmatch(){
    int res = 0;
    memset(vx,-1,sizeof(vx));
    memset(vy,-1,sizeof(vy));
    for(int i = 1;i <= m;i++){
        if(vx[i] == -1){
            memset(vis,0,sizeof(vis));
            res += path(i);
        }
    }   
    return res;
} 
int main(){
    while(cin >> k,k){
        cin >> m >> n;
        for(int i = 0;i <= n+m;i++){
            vec[i].clear();
        }
        int cnta = 1;
        int cntb = 1;
        for(int i = 0;i < k;i++){
            int x,y;
            scanf("%d%d",&x,&y);
            vec[x].push_back(y);
        }
        cout << maxmatch() << endl;;
    } 
    return 0;
}