Cod sursa(job #2569088)

Utilizator CarlaDianaCarla Diana CarlaDiana Data 4 martie 2020 11:03:00
Problema Algoritmul Bellman-Ford Scor 95
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 2.45 kb
#include <fstream>
#include <vector>
#include <queue>
#define inf 250000000
using namespace std;
ifstream fin ("bellmanford.in");
ofstream fout ("bellmanford.out");
vector <pair<int,int> >v[50010];
queue <int> q;
int n,m,a,b,c,nr[50010];
long long d[50010];
int main()
{
    fin>>n>>m;
    for(;m;m--)
    {
        fin>>a>>b>>c;
        v[a].push_back(make_pair(c,b));
        if(b==1)
        v[n+1].push_back(make_pair(c,a));
    }
    for(int i=1;i<=n;i++)
        d[i]=inf;

    d[1]=0;
    nr[1]=1;
    for(auto it:v[1])
    {
        d[it.second]=it.first;
        q.push(it.second);
    }

    while(!q.empty())
    {
        nr[q.front()]++;
        if(nr[q.front()]==n) {break;}
        for(auto it:v[q.front()])
        {
            if(d[q.front()]+it.first<d[it.second])
            {
                d[it.second]=d[q.front()]+it.first;
                q.push(it.second);
            }
        }
        q.pop();
    }


     for(auto it:v[n+1])
     {
         if(d[it.second]+it.first<0&&d[it.second]!=inf)
         {
             fout<<"Ciclu negativ!";
             return 0;
         }
     }

    for(int i=2;i<=n;i++)
        fout<<d[i]<<" ";
    return 0;
}




/*#include <fstream>
#include <vector>
#include <queue>
#define inf 250000000
using namespace std;
ifstream fin ("bellmanford.in");
ofstream fout ("bellmanford.out");
vector <pair<int,int> >v[50010];
queue <int> q;
int n,m,a,b,c,nr[50010],ma[5010][5010];
long long d[50010];
int main()
{
    fin>>n>>m;
    for(;m;m--)
    {
        fin>>a>>b>>c;
        v[a].push_back(make_pair(c,b));
    }
    for(int nod=1;nod<=n;nod++)
    {
        for(int i=1;i<=n;i++)
            d[i]=inf;
        q.push(nod);
        d[nod]=0;
        while(!q.empty())
        {
            nr[q.front()]++;
            if(nr[q.front()]==n) {break;}
            for(auto it:v[q.front()])
            {
                if(d[q.front()]+it.first<d[it.second]&&d[q.front()]!=inf)
                {
                    d[it.second]=d[q.front()]+it.first;
                    q.push(it.second);
                }
            }
            q.pop();
        }
        for(int i=1;i<=n;i++)
            ma[nod][i]=d[i];
    }

    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=n;j++)
        {
            if(ma[i][j]==inf) fout<<"x ";
            else fout<<ma[i][j]<<" ";
        }
        fout<<endl;
    }


    return 0;
}*/