Cod sursa(job #2434977)

Utilizator AlexNeaguAlexandru AlexNeagu Data 2 iulie 2019 17:46:05
Problema Algoritmul Bellman-Ford Scor 35
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.45 kb
#include <fstream>
#include <vector>
#include <queue>
#define nmax 50005
#define mmax 250005
#define oo 2000000005
using namespace std;
ifstream cin("bellmanford.in");
ofstream cout("bellmanford.out");
struct edges
{
    long a;
    long b;
    long c;
}V[nmax];
long n, m, F[nmax + 5], i, j;
vector < long > D(nmax + 5, oo);
vector < long > P[nmax + 5];
priority_queue < pair < long, long > > Q;
void Bell()
{
    pair < long, long > a;
    long long cnt = 0;
    while (!Q.empty() && cnt <= 1ll * n * m)
    {
    cnt++;
    a = Q.top();
    Q.pop();
    long node = a.second;
    F[node] = 0;
    for (i = 0; i < P[node].size(); i++)
    {
        long pos = P[node][i];
        if (D[V[pos].a] + V[pos].c < D[V[pos].b])
        {
            D[V[pos].b] = D[V[pos].a] + V[pos].c;
            if (!F[V[pos].b])
            {
                F[V[pos].b] = 1;
                Q.push({D[V[pos].b], V[pos].b});
             }
          }
       }
    }
 }
 bool Negativ()
 {
     for (long i = 1; i <= m; i++)
        if (D[V[i].a] + V[i].c < D[V[i].b])
        return true;
     return false;
 }
int main()
{
    cin >> n >> m;
    for (i = 1; i <= m; i++)
    {
        cin >> V[i].a >> V[i].b >> V[i].c;
        P[V[i].a].push_back(i);
    }
    D[1] = 0;
    Q.push({0, 1});
    Bell();
    if (Negativ()) return cout << "Ciclu negativ!\n", 0;
    for (int i = 2; i <= n; i++) cout << D[i] << " ";
    return 0;
}