Cod sursa(job #1414557)

Utilizator rares96cheseliRares Cheseli rares96cheseli Data 2 aprilie 2015 19:06:04
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.12 kb
#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream f("bellmanford.in");
ofstream g("bellmanford.out");

int N, M, D[50005], used[50005], x, y, c;
vector < pair<int, int> > G[50005];
queue < int > Q;
bool inQ[50005];

bool bellman(int sursa)
{
    for (int i=1; i<=N; ++i)
        D[i]=(1<<30);
    Q.push(sursa); D[sursa]=0; inQ[sursa]=1;

    while (Q.size())
    {
        int nod=Q.front(); Q.pop();
        inQ[nod]=0; ++used[nod];
        if (used[nod]==N) return 1;

        vector< pair<int,int> >::iterator it=G[nod].begin();
        for (; it!=G[nod].end(); ++it)
            if (D[it->first]>D[nod]+it->second)
            {
                D[it->first]=D[nod]+it->second;
                if (!inQ[it->first])
                    inQ[it->first]=1, Q.push(it->first);
            }
    }
    return 0;
}

int main()
{
    f>>N>>M;
    for (int i=1; i<=M; ++i)
    {
        f>>x>>y>>c;
        G[x].push_back(make_pair(y, c));
    }

    if (bellman(1)) g<<"Ciclu negativ!\n";
        else for (int i=2; i<=N; ++i)
            g<<D[i]<<' ';
    return 0;
}