Cod sursa(job #2870129)

Utilizator anastasei_tudorAnastasei Tudor anastasei_tudor Data 12 martie 2022 09:48:13
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.44 kb
#include <bits/stdc++.h>
#define INF 1000000004
#define NMAX 50004

using namespace std;
ifstream fin ("bellmanford.in");
ofstream fout ("bellmanford.out");

int n, m;
int dp[NMAX];
int fr[NMAX];
vector < pair <int, int> > G[NMAX];
queue <int> Q;

void citire();
bool Bellman_Ford(int start);
void afisare();

int main()
{
    citire();
    afisare();
    return 0;
}

void citire()
{
    int x, y, c;
    fin >> n >> m;
    for (int i = 1; i <= m; i++)
    {
        fin >> x >> y >> c;
        G[x].push_back({y, c});
    }

    for (int i = 1; i <= n; i++)
        dp[i] = INF;
}

bool Bellman_Ford(int start)
{
    Q.push(start);
    dp[start] = 0;
    fr[start]++;

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

        for (int i = 0; i < G[nod].size(); i++)
        {
            int vf = G[nod][i].first;
            int cost = G[nod][i].second;
            if (dp[vf] > dp[nod] + cost)
            {
                dp[vf] = dp[nod] + cost;
                fr[vf]++;
                Q.push(vf);
                if (fr[vf] == n)
                    return 0;
            }
        }
    }
    return 1;
}

void afisare()
{
    if (Bellman_Ford(1))
    {
        for (int i = 2; i <= n; i++)
            if (dp[i] == INF)
                fout << 0 << ' ';
            else
                fout << dp[i] << ' ';
    }
    else
        fout << "Ciclu negativ!";
}