POJ1860Currency Exchange spfa

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#include <cstdio>#include <cstring>#include <cmath>#include <algorithm>#include <climits>#include <string>#include <iostream>#include <map>#include <cstdlib>#include <list>#include <set>#include <queue>#include <stack>using namespace std;int n,m,tot;int head[1000];bool vis[1000];double dist[1000];int num[1000];double money;struct bian{    int v,next;    double tax,rate;}edge[1000];void add(int u,int v,double rate,double tax){    edge[tot].v=v;    edge[tot].rate=rate;    edge[tot].tax=tax;    edge[tot].next=head[u];    head[u]=tot++;}int spfa(int s){    queue<int>q;    memset(dist,0,sizeof(dist));    memset(num,0,sizeof(num));    memset(vis,0,sizeof(vis));    dist[s]=money;    q.push(s);    vis[s]=true;    num[s]++;    while(!q.empty())    {        int u=q.front();        q.pop();vis[u]=false;        for(int cur=head[u];cur!=-1;cur=edge[cur].next)        {            int v=edge[cur].v;            if(dist[v]<(dist[u]-edge[cur].tax)*edge[cur].rate)            {                dist[v]=(dist[u]-edge[cur].tax)*edge[cur].rate;                if(!vis[v])                {                    vis[v]=true;                    num[v]++;                    if(num[v]>=n) return 1;                    q.push(v);                }            }        }    }    return 0;}int main(){    int a,b,s;    double ab,t1,ba,t2;    tot=0;    cin>>n>>m>>s>>money;    memset(head,-1,sizeof(head));    for(int i=0;i<m;i++)    {        cin>>a>>b>>ab>>t1>>ba>>t2;        add(a,b,ab,t1);        add(b,a,ba,t2);    }    if(spfa(s)) printf("YES\n");    else printf("NO\n");    return 0;}
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