Cod sursa(job #3272251)

Utilizator BogdancxTrifan Bogdan Bogdancx Data 29 ianuarie 2025 00:05:02
Problema Algoritmul Bellman-Ford Scor 15
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.4 kb
#include <vector>
#include <iostream>
#include <climits>
#include <fstream>

using namespace std;

vector<int> bellman(const vector<vector<pair<int, int>>>& graph, int n, int start)
{
    vector<int> dist(n + 1, INT_MAX);
    vector<int> pred(n + 1, -1);

    dist[start] = 0;

    for (int k = 1; k <= n - 1; k++) {
        for (int i = 1; i <= n; i++) {
            for (auto [neigh, cost] : graph[i]) {
                if (dist[i] != INT_MAX && dist[i] + cost < dist[neigh]) {
                    dist[neigh] = dist[i] + cost;
                    pred[neigh] = i;
                }
            }
        }
    }

    for (int i = 1; i <= n; i++) {
        for (auto [neigh, cost] : graph[i]) {
            if (dist[i] != INT_MAX && dist[i] + cost < dist[neigh]) {
                cout << "Ciclu negativ!";
                return {};
            }
        }
    }

    return dist;
}

int main()
{
    ifstream fin("bellmanford.in");
    ofstream fout("bellmanford.out");
    int n, m;

    fin >> n >> m;

    vector<vector<pair<int, int>>> graph(n + 1);

    for (int i = 0; i < m; i++) {
        int a, b, c;
        fin >> a >> b >> c;
        graph[a].emplace_back(b, c);
    }

    vector<int> result = bellman(graph, n, 1);

    if (!result.empty()) {
        for (int i = 2; i <= n; i++) {
            fout << result[i] << ' ';
        }
    }

    return 0;
}