Cod sursa(job #2819011)

Utilizator andreea_07Andreea Georgescu andreea_07 Data 17 decembrie 2021 17:04:25
Problema Algoritmul Bellman-Ford Scor 35
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.59 kb
#include <bits/stdc++.h>

using namespace std;

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


vector<pair<int, int>>graf[50001];
vector <int> distanta;
vector <int> loop;
vector <bool> viz;
queue <int> coada;
int n,m;


int BFord(int s)
{
    int nod;
    bool ok=0;


    distanta[s]=0;
    viz[s]=1;
    coada.push(s);


    while(!coada.empty() && !ok)
    {
        nod = coada.front();
        coada.pop();
        viz[nod] = 0;


        for(int i=0; i<graf[nod].size(); i++)
        {
            int vecin=graf[nod][i].first;
            int cost=graf[nod][i].second;


            if( distanta[nod] + cost < distanta[vecin])
            {
                distanta[vecin]=distanta[nod] + cost;

                if(!viz[vecin])
                {
                    coada.push(vecin);
                    viz[vecin]=1;
                }

                loop[vecin]++;

                if(loop[vecin]>= n)
                {
                    ok=1;
                    break;
                }
            }

        }

    }

    return ok;

}



int main()
{
    int x,y,c;
    fin>>n>>m;


    for(int i=0; i<m; i++)
    {

        fin>>x>>y>>c;
        graf[x].push_back(make_pair(y,c));
    }

    for(int i=1; i<=n+1; i++)
    {
        distanta.push_back(INT_MAX);
        loop.push_back(0);
        viz.push_back(0);
    }

    if( BFord(1)!=0)
        fout<<"ciclu negativ!";

    else
    {
        for(int i=2; i<= n; i++)
            fout<<distanta[i]<<" ";

    }



    return 0;
}