Cod sursa(job #3138825)

Utilizator PostoacaMateiMatei Postoaca PostoacaMatei Data 22 iunie 2023 17:28:05
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.55 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

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

int n, m, p, dist[100001], viz[100001];
vector<pair<int, int>> gf[100001];
queue<pair<int, int>> q;
const int INF = 2e9;
int iq[100001]; // numara de cate ori apare un nod in coada

int bellman_ford(int start) {
    dist[start] = 0;
    q.push({ dist[start], start });
    viz[start] = 1;
    while (!q.empty()) {
        int nod = q.front().second; // nod e din coada
        q.pop();
        viz[nod] = 0;
        for (auto vecin : gf[nod]) {
            int costnou = vecin.first; // nodnou si costnou sunt din graf
            int nodnou = vecin.second;
            if (dist[nodnou] > dist[nod] + costnou) {
                dist[nodnou] = dist[nod] + costnou;
                if (!viz[nodnou]) {
                    iq[nodnou]++;
                    if (iq[nodnou] > n) {
                        return 0;
                    }
                    viz[nodnou] = 1;
                    q.push({ dist[nodnou], nodnou });
                }
            }
        }
    }
    return 1;
}

int main()
{
    fin >> n >> m;
    for (int i = 1; i <= m; i++) {
        int x, y, c;
        fin >> x >> y >> c;
        gf[x].push_back({ c, y });
    }
    for (int i = 0; i <= n + 1; i++)
        dist[i] = INF;
    if (bellman_ford(1))
        for (int i = 2; i <= n; i++)
            fout << dist[i] << " ";
    else
        fout << "Ciclu negativ!";
    return 0;
}