Cod sursa(job #3212370)

Utilizator CobzaruAntonioCobzaru Paul-Antonio CobzaruAntonio Data 11 martie 2024 17:32:34
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.54 kb
#include <fstream>
#include <queue>
using namespace std;
ifstream cin ("bellmanford.in");
ofstream cout ("bellmanford.out");
int d[50005];
int cnt[50005];
vector< pair<int,int> > g[50005];
int n,m;
struct chestie
{
    int d;
    int vf;
};
class Comparare
{
public:
bool operator() (chestie a,chestie b)
{
    return a.d>=b.d;
}
};
priority_queue<chestie,vector<chestie>,Comparare> pq;
void bellman(int start)
{
    for(int i=1;i<=n;i++)
        d[i] = 2e9;
    d[start] = 0;
    chestie aux;
    aux.d = 0;
    aux.vf = start;
    pq.push(aux);
    while(!pq.empty())
    {
        aux = pq.top();
        pq.pop();
        if(d[aux.vf]!=aux.d)
            continue;
        for(auto muchie:g[aux.vf])
        {
            if(d[muchie.first] > aux.d + muchie.second)
            {
                cnt[muchie.first]++;
                if(cnt[muchie.first]==n+1)
                {
                    cout << "Ciclu negativ!";
                    return;
                }
                d[muchie.first] = aux.d + muchie.second;
                chestie noua;
                noua.vf = muchie.first;
                noua.d = d[muchie.first];
                pq.push(noua);
            }
        }
    }
    for(int i=2;i<=n;i++)
        cout << d[i] << ' ';
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> m;
    for(int i=1;i<=m;i++)
    {
        int a,b,c;
        cin >> a >> b >> c;
        g[a].push_back({b,c});
    }
    bellman(1);
    return 0;
}