poj1860Currency Exchange(bell_fordmoban)

http://poj.org/problem?id=1860

模板提

 #include <iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<stdlib.h>
 #include<vector>
 #include<queue>
 #include<cmath>
 using namespace std;
 #define INF 0xfffffff
 double dis[],v;
 int n,m;
 struct node
 {
     int r,c;
     double r1,c1,r2,c2;
 }p[];
 int bell_ford(int s)
 {
     int i,j;
     memset(dis,,sizeof(dis));
     dis[s] = v;
     for(i = ; i <= n ; i++)
     {
         int flag = ;
         for(j = ; j <= m ; j++)
         {
             if((dis[p[j].r]-p[j].c1)*p[j].r1>dis[p[j].c])
             dis[p[j].c] = (dis[p[j].r]-p[j].c1)*p[j].r1;
             if((dis[p[j].c]-p[j].c2)*p[j].r2>dis[p[j].r])
             dis[p[j].r] = (dis[p[j].c]-p[j].c2)*p[j].r2;
             flag = ;

         }
         if(!flag) break;
     }
     for(j = ; j <= m ; j++)
     {
         if((dis[p[j].r]-p[j].c1)*p[j].r1>dis[p[j].c])
         return ;
         if((dis[p[j].c]-p[j].c2)*p[j].r2>dis[p[j].r])
         return ;
     }
     return ;
 }
 int main()
 {
     int i,s;
     while(scanf("%d%d%d%lf",&n,&m,&s,&v)!=EOF)
     {
         for(i = ; i <= m ; i++)
         {
             scanf("%d%d%lf%lf%lf%lf",&p[i].r,&p[i].c,&p[i].r1,&p[i].c1,&p[i].r2,&p[i].c2);
         }
         if(bell_ford(s))
         {
             puts("YES");
         }
         else
         puts("NO");
     }
     return ;
 }