Cod sursa(job #2722071)

Utilizator Razvan48Capatina Razvan Nicolae Razvan48 Data 12 martie 2021 16:15:35
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.58 kb
#include <fstream>
#include <vector>
#include <climits>
#include <queue>

using namespace std;

const int NMAX = 50000;

vector<pair<int, int>> graf[1 + NMAX];

int costuri[1 + NMAX];

queue<int> q;

bool inCoada[1 + NMAX];

int frecv[1 + NMAX];

int main()
{
    ifstream in("bellmanford.in");
    ofstream out("bellmanford.out");

    int n, m;

    in >> n >> m;

    for (int i = 1; i <= m; i++)
    {
        int x, y, c;

        in >> x >> y >> c;

        graf[x].emplace_back(make_pair(y, c));
    }

    costuri[1] = 0;

    for (int i = 2; i <= n; i++)
    {
        costuri[i] = INT_MAX;
    }

    q.emplace(1);
    inCoada[1] = true;

    while (!q.empty())
    {
        int nod = q.front();
        q.pop();
        inCoada[nod] = false;

        for (int i = 0; i < graf[nod].size(); i++)
        {
            if (costuri[graf[nod][i].first] > costuri[nod] + graf[nod][i].second)
            {
                costuri[graf[nod][i].first] = costuri[nod] + graf[nod][i].second;

                frecv[graf[nod][i].first]++;

                if (frecv[graf[nod][i].first] == n)
                {
                    out << "Ciclu negativ!" << '\n';

                    return 0;
                }

                if (!inCoada[graf[nod][i].first])
                {
                    q.emplace(graf[nod][i].first);
                    inCoada[graf[nod][i].first] = true;
                }
            }
        }
    }

    for (int i = 2; i <= n; i++)
    {
        out << costuri[i] << ' ';
    }

    return 0;
}