POJ 1860 Currency Exchange

//Time 16ms, Memory 244K

#include<iostream>#include<cstring>using namespace std;int cnt,n,m,s;double v;struct point{    int a,b;    double r,c;    point(int a=0,int b=0,double r=0.0,double c=0.0):a(a),b(b),r(r),c(c){}}p[201];int bellman(){    int i,j;    int flag;    double dis[101];    memset(dis,0,sizeof(dis));    dis[s]=v;    for(i=1;i<n;i++)    {        flag=0;        for(j=0;j<cnt;j++)        {            if(dis[p[j].b]<(dis[p[j].a]-p[j].c)*p[j].r)            {                dis[p[j].b]=(dis[p[j].a]-p[j].c)*p[j].r;flag=1;            }        }        if(!flag) break;    }    for(j=0;j<cnt;j++)    {        if(dis[p[j].b]<(dis[p[j].a]-p[j].c)*p[j].r) return 1;    }    return 0;}int main(){    int i,a,b;    double r1,r2,c1,c2;    cin>>n>>m>>s>>v;    cnt=0;    for(i=0;i<m;i++)    {        cin>>a>>b>>r1>>c1>>r2>>c2;        p[cnt++]=point(a,b,r1,c1);        p[cnt++]=point(b,a,r2,c2);    }    if(bellman()) cout<<"YES"<<endl;    else cout<<"NO"<<endl;    return 0;}