HDU 2063 过山车( 最大匹配 )

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cmath>
#include<set>
#include<map>
#include<string>
#include<cstring>
#include<stack>
#include<queue>
#include<vector>
#include<limits>
#include<ctime>
#include<cassert>
#include<cstdlib>
#define lson (rt<<1),L,M
#define rson (rt<<1|1),M+1,R
#define M ((L+R)>>1)
#define cl(a,b) memset(a,b,sizeof(a));
#define LL long long
#define P pair<int,int>
#define X first
#define Y second
#define pb push_back
#define fread(a) freopen(a,"r",stdin);
#define fwrite(a) freopen(a,"w",stdout);
using namespace std;
const int maxn=505;
const int inf=999999;

vector<int> G[maxn];
int matching[maxn];
bool vis[maxn];
int num;
bool dfs(int u){
int N=G[u].size();
for(int i=0;i<N;i++){
int v=G[u][i];
if(vis[v])continue;
vis[v]=true;
if(matching[v]==-1||dfs(matching[v])){
matching[v]=u;
return true;
}
}
return false;
}
int hungar(){
int ans=0;
cl(matching,-1);
for(int i=0;i<num;i++){
cl(vis,false);
if(dfs(i))ans++;
}
return ans;
}

int main(){
int n,m,k;
while(~scanf("%d",&k)&&k){
scanf("%d%d",&m,&n);
for(int i=0;i<maxn;i++)G[i].clear();
while(k--){
int x,y;
scanf("%d%d",&x,&y);
x--;y--;
G[x].pb(y);
}
num=max(n,m);
printf("%d\n",hungar());

}
return 0;
}