> WA
> 
> #include<iostream>
> #define maxv 505
> using namespace std;
> bool connected[maxv][maxv];
> int pre[maxv],ans,v;
> bool used[maxv];
> bool dfs(int t)
> {
>     for(int i=1;i<=v;i++)
>     {
>         if(connected[t][i] && !used[i])
>         {
>             used[i]=true;
>             if(pre[i]==-1 || dfs(i))
>             {
>                 pre[i]=t;
>                 return true;
>             }
>         }
>     }
>     return false;
> }
> int match()
> {
>     ans=0;
>     memset(pre,-1,sizeof(pre));
>     for(int i=1;i<=v;i++)
>     {
>         memset(used,0,sizeof(used));
>         if(dfs(i))
>             ans++;
>     }
>     return ans;
> }
> int main()
> {
>     int a,b,e;
>     scanf("%d%d",&v,&e);
>     memset(connected,0,sizeof(connected));
>     for(int i=1;i<=e;i++)
>     {
>         scanf("%d%d",&a,&b);
>         connected[a][b]=1;
>     }
>     printf("%d\n",match());
>     return 0;
> }
> 
> 
> AC
> 
> 
> #include <iostream>
> #include <stdlib.h>
> #define MAX 501
> 
> using namespace std;
> 
> bool used[MAX];
> int match[MAX],res;
> bool mat[MAX][MAX];
> 
> bool passway(int k,int n){//察看第k个点出发能否有增广路经
>     int i;
>     for(i=1;i<=n;i++)
>     {
>         if(mat[k][i])
>         {//k和i邻接
>            if(!used[i])
>            {
>                used[i] =1;
>                if(match[i]==-1 || passway(match[i],n))
>                {
>                    match[i] = k;
>                    return true;
>                }
>            }
>         }
>     }
>     return false;
> }
> 
> void hungary(int n)
> {
>     memset(match,-1,sizeof(match));
>    
>     for(int i=1;i<=n;i++)
>     {
>         memset(used,0,sizeof(used));
>         if(passway(i,n)) 
>             res++;
>     }
> }
> 
> int main(int argc, char *argv[])
> {
> int i,j,k,n,c,r;
> memset(mat,0,sizeof(mat));
> 
> scanf("%d%d",&n,&k);
> 
> for(i=1;i<=k;i++)
> {
>       scanf("%d%d",&r,&c);
>       mat[r][c] = 1;
> }
> 
> res = 0;
> hungary(n);
> printf("%d\n",res);
> 
> system("PAUSE");   
> return 0;
> }