bool spfa(int &flow,int &cost){
memset(dist,0x3f,sizeof(dist));
dist[S]=0;
q.init(N);
q.push(S);
while(!q.empty()){
int u=q.front();
q.pop();
for(int i=le[u]; i!=-1; i=pe[i]){
Edge &e=edges[i];
if(e.data){
if(dist[e.v]>dist[u]+e.cost){
dist[e.v]=dist[u]+e.cost;
pre[e.v]=i;
q.push(e.v);
}
}
}
}
if(dist[T]>=INF)return false;
int u=T;
while(u!=S){
Edge &e=edges[pre[u]];
edges[pre[u]].data--;
edges[1^pre[u]].data++;
u=edges[pre[u]].u;
}
cost+=dist[T];
flow++;
return true;
}
typename std::enable_if<container_traits::has_front<S>::value, const T&>::type
front_adapter () const { return queue.front(); };
