最小费用最大流模板

///最小费用最大流模板
bool spfa()
{
     fill(vs,vs+n+2,false);
     fill(d,d+n+2,inf);
     fill(father,father+n+2,-1);
     queue<int>q;
     d[0]=0;
     q.push(0);
     while (!q.empty())
     {
         int u=q.front();
         q.pop();
         vs[u]=false;
         for (int i=head[u];i!=-1;i=eage[i].next)
         {
             int v=eage[i].v;
             if (eage[i].cap&&d[v]>d[u]+eage[i].cost)
             {
                 d[v]=d[u]+eage[i].cost;
                 father[v]=i;
                 if (!vs[v])
                 {
                     vs[v]=true;
                     q.push(v);
                 }
             }
         }
     }
     if (father[n+1]==-1) return false;
     return true;
}

int solve()
{
    int ans=0;
    while (spfa())
    {
        ans+=d[n+1];
        int u=n+1;
        while (u!=0)
        {
            int i=father[u];
            eage[i].cap--;
            eage[i^1].cap++;
            u=eage[i].u;
        }
    }
    return ans;
}