luogu1640 [SCOI2010]连续攻击游戏

二分图匹配，一边是属性值，一边是武器

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
int n, lst[1010005], uu, vv, hea[10005], cnt, ans;
bool vis[1010005];
struct Edge{
	int too, nxt;
}edge[2000005];
void add_edge(int fro, int too){
	edge[++cnt].nxt = hea[fro];
	edge[cnt].too = too;
	hea[fro] = cnt;
}
bool dfs(int x){
	for(int i=hea[x]; i; i=edge[i].nxt){
		int t=edge[i].too;
		if(!vis[t]){
			vis[t] = true;
			if(!lst[t] || dfs(lst[t])){
				lst[t] = x;
				return true;
			}
		}
	}
	return false;
}
int main(){
	cin>>n;
	for(int i=1; i<=n; i++){
		scanf("%d %d", &uu, &vv);
		add_edge(uu, i+10000);
		add_edge(vv, i+10000);
	}
	for(int i=1; i<=10000; i++){
		memset(vis, 0, sizeof(vis));
		if(!dfs(i))
			break;
		ans = i;
	}
	cout<<ans<<endl;
	return 0;
}