Cod sursa(job #2289163)

Utilizator alex.carpCarp Alexandru alex.carp Data 24 noiembrie 2018 11:44:17
Problema Algoritmul Bellman-Ford Scor 85
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.35 kb
#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream f("bellmanford.in");
ofstream g("bellmanford.out");
const int NMAX=50000;
const int oo=(1<<20);
vector<pair<int,int> >G[NMAX];
queue<int>coada;
bool incoada[NMAX],ok;
int nrap[NMAX],n,m,d[NMAX];
void citire()
{
    int x,y,z;
    f>>n>>m;
    for(int i=1;i<=m;i++)
    {
        f>>x>>y>>z;
        G[x].push_back(make_pair(y,z));
    }
}
void bellman()
{
    d[1]=0;
    for(int i=2;i<=n;i++)
        d[i]=oo;
    coada.push(1);
    incoada[1]=1;
    nrap[1]++;
    while(!coada.empty())
    {
        int ncrt=coada.front();
        coada.pop();
        incoada[ncrt]=0;
        for(int i=0;i<G[ncrt].size();i++)
        {
            int vecin=G[ncrt][i].first;
            int cost=G[ncrt][i].second;
            if(d[vecin]>d[ncrt]+cost)
            {
                d[vecin]=d[ncrt]+cost;
                if(incoada[vecin]==0)
                {
                    coada.push(vecin);
                    incoada[vecin]=1;
                    nrap[vecin]++;
                    if(nrap[vecin]>=n){g<<"Ciclu negativ!";ok=1;return;}
                }
            }
        }
    }
}
void afisare()
{
    for(int i=2;i<=n;i++)
        g<<d[i]<<" ";
}
int main()
{
    citire();
    bellman();
    if(ok==0)afisare();

    return 0;
}