Cod sursa(job #2302935)

Utilizator victorv88Veltan Victor victorv88 Data 15 decembrie 2018 11:43:10
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.44 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

ifstream f("bellmanford.in");
ofstream g("bellmanford.out");

queue<int >q;
vector<pair<int,int> >graph[50005];

int n, m, from, to, cost, distante[50005], nr_coada[50005], ok=0;
bool in_coada[50005];

int rezolvare()
{
    ok=0;
    q.push(1);
    in_coada[1]=true;
    nr_coada[1]++;
    while (!q.empty() && ok==0)
    {
        int nod_actual=q.front();
        q.pop();
        in_coada[nod_actual]=false;
        for (auto &v:graph[nod_actual])
        {
            if (distante[nod_actual]+v.second<distante[v.first])
            {
                distante[v.first]=distante[nod_actual]+v.second;
                if (!in_coada[v.first])
                {
                    in_coada[v.first]=1;
                    nr_coada[v.first]++;
                    q.push(v.first);
                    if (nr_coada[v.first]>n)
                    {
                        return 0;
                    }
                }
            }

        }
    }
    return 1;
}

int main() {
    f >> n >> m;
    for (int i=1; i<=m; i++)
    {
        f >> from >> to >> cost;
        graph[from].push_back(make_pair(to,cost));
    }
    for (int i=2; i<=n; i++)
        distante[i]=(1<<28);
    if (rezolvare()==1)
    {
        for (int i=2; i<=n; i++)
        {
            g << distante[i] <<' ';
        }
    }
    else
    {
        g << "Ciclu negativ!";
    }
    return 0;
}