Submission #1609596

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;


struct Edge
{
    long long from;
    long long to;
    long long cost;
}edge[1000000];
long long dis[1010];
long long vertex,edge_num;
#define inf 10000000000
bool flag[1010];
void Bellman_fold(long long s)
{
    memset(flag,0,sizeof(0));
    for(long long i=1;i<=vertex;++i)
    {
        dis[i]=inf;
    }
    dis[s]=0;
    for(long long i=1;i<vertex;++i)
    {
        for(int j=0;j<edge_num;++j)
        {
            if(dis[edge[j].from]!=inf&&dis[edge[j].from]+edge[j].cost<dis[edge[j].to])
                {
                    dis[edge[j].to]=dis[edge[j].from]+edge[j].cost;
                }
        }
    }
    for(long long i=1;i<=vertex;++i)
    {
        for(int j=0;j<edge_num;++j)
        {
            if(flag[edge[j].from]==true)
            {
                flag[edge[j].to]=true;
            }
            if(dis[edge[j].from]!=inf&&dis[edge[j].from]+edge[j].cost<dis[edge[j].to])
                {
                    dis[edge[j].to]=dis[edge[j].from]+edge[j].cost;
                    flag[edge[j].to]=true;
                }
        }
    }
}

int main(void)
{

    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin>>vertex>>edge_num;
    long long from,to,weight;
    for (int i=0;i<edge_num;++i)
    {
        cin>>edge[i].from>>edge[i].to>>weight;
        edge[i].cost=weight*(-1);
    }
    Bellman_fold(1);
    if(!flag[vertex])
    {
        cout <<dis[vertex]*(-1)<<endl;
    }
    else
    {
        cout <<"inf"<<endl;
    }


    return 0;
}

Submission Info

Judge Result