Cod sursa(job #1402720)

Utilizator cautionPopescu Teodor caution Data 26 martie 2015 19:16:36
Problema Algoritmul Bellman-Ford Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.54 kb
#include <fstream>
#include <queue>
#include <vector>
#define INF 123456789
using namespace std;

int main()
{
    ifstream in("bellmanford.in");
    ofstream out("bellmanford.out");
    vector<pair<long, long> > *graf;
    queue<long> Q;
    bool *in_queue, stop=false;
    long *times_in_queue, *dist;
    long n, m, a, b, c;
    in>>n>>m;
    graf = new vector<pair<long, long> >[n+1];
    in_queue = new bool[n+1];
    times_in_queue = new long[n+1];
    dist = new long[n+1];
    for(long i=0; i<m; ++i)
    {
        in>>a>>b>>c;
        graf[a].push_back(make_pair(b, c));
    }
    for(long i=1; i<=n; ++i)
    {
        times_in_queue[i]=0;
        in_queue[i]=false;
        dist[i]=INF;
    }
    in_queue[1]=true;
    dist[1]=0;
    Q.push(1);
    times_in_queue[1]=1;
    while(!Q.empty()&&!stop)
    {
        a=Q.front();
        Q.pop();
        for(vector<pair<long, long> >::iterator it=graf[a].begin(), ed=graf[a].end(); it!=ed; ++it)
        {
            if(dist[it->first]>dist[a]+it->second)
            {
                dist[it->first]=dist[a]+it->second;
                ++times_in_queue[it->first];
                if(times_in_queue[it->first]>n) stop=true;
                if(!in_queue[it->first])
                {
                    in_queue[it->first]=true;
                    Q.push(it->first);
                }
            }
        }
    }
    if(stop) out<<"Ciclu negativ!\n";
    else
        for(long i=2; i<=n; ++i) out<<dist[i]<<' ';
    in.close(); out.close();
    return 0;
}