Cod sursa(job #1202925)

Utilizator AdrianaMAdriana Moisil AdrianaM Data 30 iunie 2014 02:37:19
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.46 kb
#include <fstream>
#include <vector>
#include <queue>
#define INF 0x3f3f3f3f
using namespace std;

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

int n, m;
vector<vector<pair<int, int> > > g;
vector<int> d;
vector<int> cnt;
queue<int> q;

void READ();
void SOLVE();
void WRITE();

int main()
{
    READ();
    SOLVE();
    is.close();
    os.close();
    return 0;
}

void SOLVE()
{
    d[1] = 0;
    q.push(1);
    int i;
    while ( !q.empty() )
    {
        i = q.front();
        q.pop();
        ++cnt[i];
        if ( cnt[i] >= n )
        {
            os << "Ciclu negativ!";
            return;
        }
        //os << i << ":\n";
        for ( vector<pair<int, int> >::iterator it = g[i].begin(); it != g[i].end(); ++it )
        {
            //os << it->second << "-> ";
            if ( d[it->second] > d[i] + it->first )
            {
                d[it->second] = d[i] + it->first;
                q.push(it->second);
            }
            //os << d[it->second] << "<- ";
        }
    }
    WRITE();
}

void READ()
{
    is >> n >> m;
    g.resize(n + 1);
    cnt.resize(n + 1);
    d.resize(n + 1, INF);
    int x, y, z;
    while ( m-- )
    {
        is >> x >> y >> z;
        g[x].push_back(make_pair(z, y));
    }
}

void WRITE()
{
    for ( int i = 2; i <= n; ++i )
        if ( d[i] == INF )
            os << "0 ";
        else
            os << d[i] << " ";
}