Cod sursa(job #1231829)

Utilizator AdrianaMAdriana Moisil AdrianaM Data 21 septembrie 2014 17:02:22
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.43 kb
#include <fstream>
#include <vector>
#include <queue>
#define INF 0x3f3f3f3f
using namespace std;

ifstream is("bellmanford.in");
ofstream os("bellmanford.out");

int n, m, x, y, z;
vector<bool> ok;
queue<int> q;
vector<int> d, cnt;
vector<vector<pair<int, int> > > g;

int main()
{
    is >> n >> m;
    vector<int> d(n + 1, INF);
    vector<int> cnt(n + 1);
    g.resize(n + 1);
    ok.resize(n + 1);
    for ( int i = 1; i <= m; ++i )
    {
        is >> x >> y >> z;
        g[x].push_back(make_pair(z, y));
    }
    d[1] = 0;
    q.push(1);
    ok[1] = true;
    while ( !q.empty() )
    {
        x = q.front();
        q.pop();
        ok[x] = false;
        for ( vector<pair<int, int> >::iterator it = g[x].begin(); it != g[x].end(); ++it )
        {
            y = it->second;
            z = it->first;
            if ( d[y] > d[x] + z )
            {
                d[y] = d[x] + z;
                //os << d[y] << " ";
                if ( !ok[y] )
                {
                    ++cnt[y];
                    if ( cnt[y] == n )
                    {
                        os << "Ciclu negativ!";
                        return 0;
                    }
                    q.push(y);
                    ok[y] = true;
                }
            }
        }
    }
    for ( int i = 2; i <= n; ++i )
        os << d[i] <<" ";
    is.close();
    os.close();
    return 0;
}