Cod sursa(job #1878611)

Utilizator andrei.sasaAndrei SaSa andrei.sasa Data 14 februarie 2017 12:11:22
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.35 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define MAXX 250010
#define NMAX 50010

using namespace std;

ifstream f("bellmanford.in");
ofstream g("bellmanford.out");

vector <pair <int, int> > G[NMAX];

int n,m,frecv[NMAX],d[NMAX],inq[NMAX];

void Bellman_Ford()
{
    for(int i=1;i<=n;i++)
        d[i]=MAXX;
    queue <int> q;
    q.push(1);
    inq[1]=1;
    d[1]=0;
    while(!q.empty())
    {
        int nod=q.front();
        q.pop();
        inq[nod]=0;
        for(int i=0;i<G[nod].size();i++)
            {
                if(d[G[nod][i].first]>d[nod]+G[nod][i].second)
                {
                    d[G[nod][i].first]=d[nod]+G[nod][i].second;
                    if(inq[G[nod][i].first]) continue;
                    if(++frecv[G[nod][i].first]>n)
                        {
                            g<<"Ciclu negativ!";
                            g.close();
                            return;
                        }
                    inq[G[nod][i].first]=1;
                    q.push(G[nod][i].first);
                }
            }
    }
    for(int i=2;i<=n;i++)
        g<<d[i]<<' ';
}

int main()
{
    f>>n>>m;
    while(m--)
    {
        int a,b,c;
        f>>a>>b>>c;
        G[a].push_back(make_pair(b,c));
    }
    Bellman_Ford();
    return 0;
}