hdu4280 最大流DINIC

题意:

      x最小的到x最大的点同一时间的最大运输量.

思路:

      裸的最大流,不解释,注意一点,记得加上防爆栈.

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<stdio.h>
#include<string.h>
#include<queue>
#define N 300000
using namespace std;
struct  star
{
   int b,c,next;
}D[N];
struct mknum
{
    int x,t;
}tou,xin;
queue<mknum>q;
int minn(int x,int y)
{
  return x<y?x:y;
}
int list1[100005],list2[100005],tot;
int  deep[100005];
void add(int a,int b,int c)
{
   D[++tot].b=b;
   D[tot].c=c;
   D[tot].next=list1[a];
   list1[a]=tot;
}
bool bfs(int s,int t,int n)
{
   memset(deep,255,sizeof(deep));
   deep[s]=0;
   xin.x=s;
   xin.t=0;
   while(!q.empty())
   q.pop();
   q.push(xin);
   while(!q.empty())
   {
      tou=q.front();
      q.pop();
      for(int k=list1[tou.x];k;k=D[k].next)
      {
          int to=D[k].b;
          if(deep[to]==-1&&D[k].c)
          {
        xin.x=to;
        xin.t=tou.t+1;
        q.push(xin);
        deep[xin.x]=xin.t;
           }
       }
      }

      for(int i=0;i<=n;i++)
      list2[i]=list1[i];
      return deep[t]!=-1;
}                    

int dfs(int s,int t,int flow)
{
     if(s==t)
     return flow;
     int nowflow=0;
     for(int k=list2[s];k;k=D[k].next)
     {
          list2[s]=k;
    int to=D[k].b;
    int c=D[k].c;
    if(deep[to]!=deep[s]+1||!c)
    continue;
    if(nowflow==flow)
    break;
    int temp=dfs(to,t,minn(c,flow-nowflow));
    nowflow+=temp;
    D[k].c-=temp;
    D[k^1].c+=temp;
    if(nowflow==flow)
    break;
       }
        if(nowflow==0)
        deep[s]=0;
        return nowflow;
}

int DINIC(int s,int t,int n)
{
  int ans=0;
  while(bfs(s,t,n))
  {
     ans+=dfs(s,t,1000000000);
   }
   return ans;
}

int main ()
{
   int i,n,m,mx,mi,s,t,tt,a,b,c,x,y;
   scanf("%d",&tt);
   while(tt--)
   {
      scanf("%d%d",&n,&m);
      mx=-10000000,mi=10000000;
      for(i=1;i<=n;i++)
      {
         scanf("%d%d",&x,&y);
         if(mx<x)
         {
               mx=x;
            t=i;
         }
         if(mi>x)
         {
            mi=x;
            s=i;
         }
       }
       memset(list1,0,sizeof(list1));
       tot=1;
       for(i=1;i<=m;i++)
       {
          scanf("%d%d%d",&a,&b,&c);
    add(a,b,c);
    add(b,a,c);
        }
        printf("%d\n",DINIC(s,t,n));
    }
    return 0;
}