Cod sursa(job #1329748)

Utilizator emanuel_rRamneantu Emanuel emanuel_r Data 29 ianuarie 2015 20:14:20
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.55 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],NrQ[NMax],Ok = 1;
bool InQ[NMax];

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;
}