Cod sursa(job #3251293)

Utilizator andreiomd1Onut Andrei andreiomd1 Data 25 octombrie 2024 16:50:44
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.44 kb
#include <fstream>
#include <vector>
#include <queue>

using namespace std;
using edge = pair<int, int>;

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

static constexpr int nMAX = ((int)(5e4) + 4), INF = ((int)(1e9));

int n;
vector<edge> G[nMAX];

void load_graph()
{
    int m = 0;
    f >> n >> m;

    int x = 0, y = 0, z = 0;
    for (int i = 1; i <= m; ++i)
    {
        f >> x >> y >> z;

        G[x].push_back({z, y});
    }

    return;
}

int main()
{
    load_graph();

    vector<int> d((n + 1), INF);
    vector<bool> in_queue((n + 1), false);
    vector<int> counts((n + 1), 0);

    queue<int> Q;

    d[1] = 0, in_queue[1] = true, counts[1] = 1, Q.push(1);

    while (!Q.empty())
    {
        int node = Q.front();
        Q.pop();

        in_queue[node] = false;

        for (const edge &it : G[node])
            if ((d[node] + it.first) < d[it.second])
            {
                d[it.second] = (d[node] + it.first);

                if (in_queue[it.second])
                    continue;

                ++counts[it.second];

                if (counts[it.second] >= n)
                {
                    g << "Ciclu negativ!\n";
                    return 0;
                }

                in_queue[it.second] = true, Q.push(it.second);
            }
    }

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

        if (i != n)
            g << ' ';
        else
            g << '\n';
    }

    return 0;
}