Cod sursa(job #1337725)

Utilizator AdrianaMAdriana Moisil AdrianaM Data 9 februarie 2015 13:52:04
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.42 kb
#include <fstream>
#include <queue>
#include <vector>
#include <bitset>
#define INF 0x3f3f3f3f
#define nodv g[nod][i].second
#define cost g[nod][i].first
using namespace std;

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

int n, m;
vector<int> d, cnt;
vector<vector<pair<int, int> > > g;
bitset<50001> ok;

void Read();
void BF();

int main()
{
    Read();
    BF();
    is.close();
    os.close();
    return 0;
}

void BF()
{
    queue<int> q;
    d = vector<int>(n + 1, INF);
    cnt = vector<int>(n + 1);
    d[1] = 0;
    q.push(1);
    int nod;
    while ( !q.empty() )
    {
        nod = q.front();
        q.pop();
        ok[nod] = false;
        for ( size_t i = 0; i < g[nod].size(); ++i )
            if ( d[nodv] > d[nod] + cost )
            {
                d[nodv] = d[nod] + cost;
                if ( !ok[nodv] )
                {
                    ok[nodv] = true;
                    ++cnt[nodv];
                    if ( cnt[nodv] == n )
                    {
                        os << "Ciclu negativ!";
                        return;
                    }
                    q.push(nodv);
                }
            }

    }
    for ( int i = 2; i <= n; ++i )
        os << d[i] << " ";
}

void Read()
{
    is >> n >> m;
    g = vector<vector<pair<int, int> > >(n + 1);
    int x, y, c;
    for ( int i = 1; i <= m; ++i )
    {
        is >> x >> y >> c;
        g[x].push_back(make_pair(c, y));
    }
}