【最短路】【spfa】【最小割】【Dinic】bzoj1266 [AHOI2006]上学路线route

#include<cstdio>
#include<cstring>
#include<queue>
#include<algorithm>
using namespace std;
#define INF 2147483647
#define MAXN 511
#define MAXM 505001
int n,m,S,T,Sta,End,Ws[260000],W,C;
queue<int>q;
namespace Dinic
{	
    int v[MAXM],cap[MAXM],en,first[MAXN],next[MAXM];
    int d[MAXN],cur[MAXN];
    void Init_Dinic(){memset(first,-1,sizeof(first)); en=0; S=1; T=n;}
    void AddEdge(const int &U,const int &V,const int &W)
    {v[en]=V; cap[en]=W; next[en]=first[U]; first[U]=en++;
    v[en]=U; next[en]=first[V]; first[V]=en++;}
    bool bfs()
      {
        memset(d,-1,sizeof(d)); q.push(S); d[S]=0;
        while(!q.empty())
          {
            int U=q.front(); q.pop();
            for(int i=first[U];i!=-1;i=next[i])
              if(d[v[i]]==-1 && cap[i])
                {
                  d[v[i]]=d[U]+1;
                  q.push(v[i]);
                }
          }
        return d[T]!=-1;
      }
    int dfs(int U,int a)
      {
        if(U==T || !a) return a;
        int Flow=0,f;
        for(int &i=cur[U];i!=-1;i=next[i])
          if(d[U]+1==d[v[i]] && (f=dfs(v[i],min(a,cap[i]))))
            {
              cap[i]-=f; cap[i^1]+=f;
              Flow+=f; a-=f; if(!a) break;
            }
        if(!Flow) d[U]=-1;
        return Flow;
      }
    int max_flow()
      {
        int Flow=0,tmp=0;
        while(bfs())
          {
            memcpy(cur,first,(n+5)*sizeof(int));
            while(tmp=dfs(S,INF)) Flow+=tmp;
          }
        return Flow;
      }
};
namespace SPFA
{
	int u[260000],next[260000],v[260000],first[501],w[260000],en,dis[501];
	bool inq[501];
	void AddEdge(const int &U,const int &V,const int &W,const int &C)
	{u[++en]=U; v[en]=V; w[en]=W; Ws[en]=C; next[en]=first[U]; first[U]=en;}
	void spfa(const int &s)
	  {
	  	memset(dis,0x7f,sizeof(dis));
	  	dis[s]=0; inq[s]=1; q.push(s);
	  	while(!q.empty())
	  	  {
	  	  	int U=q.front();
	  	  	for(int i=first[U];i;i=next[i])
	  	  	  if(dis[v[i]]>dis[U]+w[i])
	  	  	    {
	  	  	      dis[v[i]]=dis[U]+w[i];
	  	  	      if(!inq[v[i]])
					q.push(v[i]),inq[v[i]]=1;
	  	  	    }
	  	  	q.pop(); inq[U]=0;
	  	  }
	  }
	void Rebuild_Graph()
	  {
	  	Dinic::Init_Dinic();
	  	for(int i=1;i<=(m<<1);++i)
	  	  if(dis[u[i]]+w[i]==dis[v[i]])
	  	    Dinic::AddEdge(u[i],v[i],Ws[i]);
	  }
};
int main()
{
	scanf("%d%d",&n,&m);
	for(int i=1;i<=m;++i)
	  {
	  	scanf("%d%d%d%d",&Sta,&End,&W,&C);
	  	SPFA::AddEdge(Sta,End,W,C);
	  	SPFA::AddEdge(End,Sta,W,C);
	  }
	SPFA::spfa(1); SPFA::Rebuild_Graph();
	printf("%d\n%d\n",SPFA::dis[n],Dinic::max_flow());
	return 0;
}