Cod sursa(job #1689310)

Utilizator crysstyanIacob Paul Cristian crysstyan Data 14 aprilie 2016 09:33:40
Problema Algoritmul Bellman-Ford Scor 35
Compilator cpp Status done
Runda Arhiva educationala Marime 1.21 kb
#include <fstream>
#include <vector>
#include <algorithm>
#include <queue>
#define NMAX 50005
#define inf 2000000000

using namespace std;

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

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

void BFS()
{
    q.push(1);

    while (!q.empty())
    {
        int curr = q.front();
        q.pop();

        for (auto & it : v[curr])
            if (d[it.first] > d[curr] + it.second)
            {
                if (used[it.first] > n)
                {
                    ciclu = 1;
                    return;
                }
                else
                {
                    d[it.first] = d[curr] + it.second;
                    q.push(it.first);
                    used[it.first] ++;
                }
            }
    }
}

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

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

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

    BFS();

    if (ciclu)
        return 0;

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