Cod sursa(job #1857340)

Utilizator ZenoTeodor Anitoaei Zeno Data 26 ianuarie 2017 08:23:17
Problema Algoritmul Bellman-Ford Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.4 kb
#include <bits/stdc++.h>
#define INF 2000000000

using namespace std;

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

int n, m;

vector<int> A[50001];
vector<short> C[50001];
queue<int> Q;

int d[50001], nre[50001];
bool in[50001];

void bellman_ford(int x)
{
    int vecin, cost;
    for(int i = 1; i <= n; i++)
        d[i] = INF;
    d[x] = 0;
    Q.push(x);
    in[x] = 1;
    nre[x] = 1;
    while(!Q.empty())
    {
        int nod = Q.front();
        Q.pop();
        in[nod] = 1;
        for(int i = 0; i < A[nod].size(); i++)
        {
            vecin = A[nod][i];
            cost = C[nod][i];
            if(d[vecin] > d[nod] + cost)
            {
                d[vecin] = d[nod] + cost;
                if(in[vecin] != 1)
                {
                    in[vecin] = 1;
                    Q.push(vecin);
                    nre[vecin]++;
                    if(nre[vecin] >= n)
                    {
                        fout << "Ciclu negativ!" << '\n';
                        exit(0);
                    }
                }
            }
        }
    }
}

int main()
{
    int a, b, x;
    fin >> n >> m;
    for(int i = 0; i < m; i++)
    {
        fin >> a >> b >> x;
        A[a].push_back(b);
        C[a].push_back(x);
    }
    bellman_ford(1);
    for(int i = 2; i <= n; i++) fout << d[i] << ' ';
    return 0;
}