Cod sursa(job #3287932)

Utilizator PetrudpPetru Paun Petrudp Data 19 martie 2025 21:06:51
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.61 kb
#include <fstream>
#include <vector>
#include <queue>
#include <climits>

using namespace std;

struct nod
{
    int next, cost;
};

bool bellman_ford(int start, int n, vector<vector<nod>> &g, vector<int> &dist, vector<int> &nrq, vector<bool> &inq)
{
    queue<int> q;
    q.push(start);
    dist[start] = 0;
    inq[start] = true;
    nrq[start] = 1;
    while (!q.empty())
    {
        int x = q.front();
        q.pop();
        inq[x] = false;
        for (auto nb : g[x])
        {
            int next = nb.next, cost = nb.cost;
            if (dist[x] + cost < dist[next])
            {
                dist[next] = dist[x] + cost;
                if (!inq[next])
                {
                    q.push(next);
                    inq[next] = true;
                    nrq[next]++;
                    if (nrq[next] == n)
                    {
                        return false;
                    }
                }
            }
        }
    }
    return true;
}

int main()
{
    ifstream in("bellmanford.in");
    ofstream out("bellmanford.out");
    int n, m;
    in >> n >> m;
    vector<vector<nod>> g(n + 1);
    vector<int> dist(n + 1, INT_MAX), nrq(n + 1, 0);
    vector<bool> inq(n + 1, false);

    for (int i = 1; i <= m; i++)
    {
        int x, y, c;
        in >> x >> y >> c;
        g[x].push_back({y, c});
    }

    if (!bellman_ford(1, n, g, dist, nrq, inq))
    {
        out << "Ciclu negativ!";
    }
    else
    {
        for (int i = 2; i <= n; i++)
        {
            out << dist[i] << " ";
        }
    }

    return 0;
}