Cod sursa(job #2682679)

Utilizator DariaCretuCretu Daria Stefana DariaCretu Data 9 decembrie 2020 11:47:41
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.36 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define INF 0x3f3f3f3f
using namespace std;
ifstream f("bellmanford.in");
ofstream g("bellmanford.out");
int n,m;
vector< pair<int, int> >graf[50005];
vector <int> v;
queue <int> q;
int d[50005];
int viz[50005];
int incoada[50005];
bool bellmanford(int s)
{
    for(int i=1;i<=n;i++)
    {
        viz[i]=0;
        incoada[i]=0;
        d[i]=INF;
    }
    d[s] = 0;
    q.push(s);
    incoada[s] = 1;

    while(!q.empty())
    {
        int nodcurent = q.front();
        viz[nodcurent]++;
        if(viz[nodcurent] >= n)
            return false;
        q.pop();
        incoada[nodcurent] = 0;

        for(size_t i=0;i<graf[nodcurent].size();i++)
        {
            int vecin = graf[nodcurent][i].first;
            int cost = graf[nodcurent][i].second;
            if(d[nodcurent]+cost < d[vecin])
            {
                d[vecin] = d[nodcurent]+cost;
                if(!incoada[vecin])
                    q.push(vecin);
            }
        }
    }
    return true;
}
int main()
{f>>n>>m;

for(int i=1;i<=m;i++)
{
    int x,y,c;
    f>>x>>y>>c;
    graf[x].push_back(make_pair(y,c));
}
  if(bellmanford(1))
    {
        for(int i=2;i<=n;i++)
            g<<d[i]<<" ";
    }
    else
      g<<"Ciclu negativ!";



    return 0;
}