Cod sursa(job #1643938)

Utilizator crysstyanIacob Paul Cristian crysstyan Data 9 martie 2016 20:50:40
Problema Algoritmul Bellman-Ford Scor 10
Compilator cpp Status done
Runda Arhiva educationala Marime 1.1 kb
#include <fstream>
#include <algorithm>
#include <vector>
#include <queue>
#define NMAX 50005
#define inf 2000000000

using namespace std;

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

int used[NMAX], d[NMAX], i, j, n, m, x, y, cost;
bool exista = 0;
vector < pair < int, int > > v[NMAX];
queue < int > q;

void bellman()
{
    q.push(1);
    d[1] = 0;

    for (int i = 2; i <= n; ++ i)
        d[i] = inf;

    for (i = 1; i <= n; ++ i)
        for (auto & it : v[i])
            if (d[it.first] > d[i] + it.second)
                d[it.first] = d[i] + it.second;

    for (i = 1; i <= n; ++ i)
        for (auto & it : v[i])
            if (d[it.first] > d[i] + it.second)
    {
        exista = 1;
        break;
    }
}

int main()
{
    f >> n >> m;

    for (i = 1; i <= m; ++ i)
    {
        f >> x >> y >> cost;
        v[x].push_back(make_pair(y, cost));
    }

    bellman();

    if (exista)
    {
        g << "Ciclu negativ!" << '\n';
        return 0;
    }

    for (i = 2; i <= n; ++ i)
        g << d[i] << " ";
    return 0;
}