hdu 3435 A new Graph Game

http://acm.hdu.edu.cn/showproblem.php?pid=3435

 #include <cstdio>
 #include <iostream>
 #include <cstring>
 #include <queue>
 #include <algorithm>
 #define inf 0x3f3f3f3f
 #define maxn 54444
 using namespace std;

 queue<int>q;
 struct node
 {
     int u,v,next,val,f;
 } p[maxn];
 int head[maxn];
 bool vis[maxn];
 int dis[maxn];
 int pre[maxn];
 int n,m,s,t,e;

 void add(int u,int v,int f,int c)
 {
     p[e].u=u;
     p[e].v=v;
     p[e].f=f;
     p[e].val=c;
     p[e].next=head[u];
     head[u]=e++;
     p[e].u=v;
     p[e].v=u;
     p[e].f=;
     p[e].val=-c;
     p[e].next=head[v];
     head[v]=e++;

 }

 bool spfa()
 {
     int j,k,i;
     while(!q.empty()) q.pop();
     memset(vis,false,sizeof(vis));
     memset(dis,0x3f,sizeof(dis));
     memset(pre,-,sizeof(pre));
     vis[s]=true;
     dis[s]=;
     q.push(s);
     while(!q.empty())
     {
         int u=q.front();
         q.pop();
         vis[u]=false;
         for(j=head[u]; j!=-; j=p[j].next)
         {
             int v=p[j].v;
             if(p[j].f&&dis[u]+p[j].val<dis[v])
             {
                 dis[v]=dis[u]+p[j].val;
                 pre[v]=j;
                 if(!vis[v])
                 {
                     vis[v]=true;
                     q.push(v);
                 }
             }
         }
     }
     return dis[t]!=inf;
 }

 int mincost()
 {
     int ret=,u;
     while(spfa())
     {
         u=pre[t];
         ret+=dis[t];
         while(u!=-)
         {
             p[u].f--;
             p[u^].f++;
             u=pre[p[u].u];
         }
     }
     return ret;
 }
 int main()
 {
     int case1;
     scanf("%d",&case1);
     for(int k=; k<=case1; k++)
     {
         e=;
         memset(head,-,sizeof(head));
         scanf("%d%d",&n,&m);
         s=;
         t=*n+;
         for(int i=; i<=m; i++)
         {
             int a,b,c;
             scanf("%d%d%d",&a,&b,&c);
             add(a,b+n,,c);
             add(b,a+n,,c);
         }
         for(int i=; i<=n; i++)
         {
             add(s,i,,);
             add(i+n,t,,);
         }
         int j;
         int ans=mincost();
         for(j=head[s]; j!=-; j=p[j].next)
          if(p[j].f!=) break;
         if(j==-) printf("Case %d: %d\n",k,ans);
         else printf("Case %d: NO\n",k);
     }
     return ;
 }