Cod sursa(job #1327943)

Utilizator hopingsteamMatraguna Mihai-Alexandru hopingsteam Data 27 ianuarie 2015 17:42:21
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.44 kb
#include <fstream>
#include <vector>
#include <queue>
#define NMax 50005
#define oo 1000000000
using namespace std;
ifstream fin("bellmanford.in");
ofstream fout("bellmanford.out");

int N,M;
vector < pair<int, int> > G[NMax];
queue <int> Q;
int D[NMax],InQ[NMax],NrQ[NMax];
int Ok=1;

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

void BellmanFord()
{
    for(int i=2;i<=N;i++)
        D[i] = oo;
    Q.push(1); InQ[1] = 1;NrQ[1]++;
    while(!Q.empty())
    {
        int Nod = Q.front();Q.pop();InQ[Nod] = 0;
        for(int i=0; i<(int)G[Nod].size();i++)
        {
            int Vecin = G[Nod][i].first, Cost = G[Nod][i].second;
            if(D[Vecin]>D[Nod]+Cost)
            {
                D[Vecin] = D[Nod] + Cost;
                if(!InQ[Vecin])
                {
                    Q.push(Vecin);
                    InQ[Vecin] = 1; NrQ[Vecin]++;
                    if(NrQ[Vecin]>N)
                    {
                        Ok = 0;
                        return;
                    }
                }

            }
        }
    }
}

void Print()
{
    if(!Ok)
    {
        fout<<"Ciclu negativ!\n";
        return;
    }
    for(int i=2;i<=N;i++)
        fout<<D[i]<<" ";
    fout<<"\n";
}

int main()
{
    Read();
    BellmanFord();
    Print();
    return 0;
}