Cod sursa(job #1331473)

Utilizator rsteliRadu Stelian rsteli Data 31 ianuarie 2015 18:29:36
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.29 kb
#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream cin("bellmanford.in");
ofstream cout("bellmanford.out");

#define nmax 50010
#define infinit 1000000000

int n,m,x,y,c,nod,vecin,cost,lg,d[nmax],ap[nmax],viz[nmax];
vector<pair<int,int> > a[nmax];
queue<int> q;

int main()
{
    int i,j;
    cin>>n>>m;
    for (i=1;i<=m;i++)
    {
        cin>>x>>y>>c;
        a[x].push_back(make_pair(y,c));
    }
    for (i=1;i<=n;i++)
        d[i]=infinit;
    d[1]=0;
    viz[1]=1;
    q.push(1);
    while (!q.empty())
    {
        nod=q.front();
        q.pop();
        viz[nod]=0;
        lg=a[nod].size();
        for (i=0;i<lg;i++)
        {
            vecin=a[nod][i].first;
            cost=a[nod][i].second;
            if (d[vecin]>d[nod]+cost)
            {
                d[vecin]=d[nod]+cost;
                if (!viz[vecin])
                {
                    if (ap[vecin]>=n)
                    {
                        cout<<"Ciclu negativ!";
                        return 0;
                    }
                    viz[vecin]=1;
                    ap[vecin]++;
                    q.push(vecin);
                }
            }
        }
    }
    for (i=2;i<=n;i++)
        cout<<(d[i]==infinit?0:d[i])<<" ";
}