POJ 1860 Currency Exchange (Bellman ford)

#include<cstdio>
#include<string>
#include<iostream>
#include<cstring>
#include<cmath>
#include<stack>
#include<queue>
#include<map>
#include<stdlib.h>
#include<algorithm>
#define LL __int64
using namespace std;
const int MAXN=200+5;
int n,m,S,tot;
int MON[2][MAXN];
double RC[2][MAXN],d[MAXN],V;
bool flag;

bool Bellman()
{
    for(int i=1;i<=n;i++)
        d[i]=0;
    d[S]=V;
    for(int i=1;i<n;i++)
    {
        bool tg=false;
        for(int j=1;j<=tot;j++)
        {
            int u=MON[0][j];
            int v=MON[1][j];
            if(d[v]<(d[u]-RC[1][j])*RC[0][j])
            {
                d[v]=(d[u]-RC[1][j])*RC[0][j];
                tg=true;
            }
        }
        if(!tg) return false;
    }
    for(int i=1;i<=tot;i++)
    {
        int u=MON[0][i];
        int v=MON[1][i];
        if(d[v]<(d[u]-RC[1][i])*RC[0][i])
            return true;
    }
    return false;
}
int main()
{
    //freopen("in.txt","r",stdin);
    while(scanf("%d %d %d %lf",&n,&m,&S,&V)!=EOF)
    {
        tot=1;
        memset(MON,0,sizeof(MON));
        memset(RC,0,sizeof(RC));

        for(int i=0;i<m;i++)
        {
            int a,b;
            double c,d,e,f;
            scanf("%d %d %lf %lf %lf %lf",&a,&b,&c,&d,&e,&f);
            MON[0][tot]=a;
            MON[1][tot]=b;
            RC[0][tot]=c;
            RC[1][tot]=d;
            tot++;
            MON[0][tot]=b;
            MON[1][tot]=a;
            RC[0][tot]=e;
            RC[1][tot]=f;
            tot++;
        }

        if(Bellman()) printf("YES\n");
        else printf("NO\n");
    }
    return 0;
}