Cod sursa(job #2672284)

Utilizator grigorut_octavianGrigorut Dominic Octavian grigorut_octavian Data 13 noiembrie 2020 16:27:04
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.42 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define oo 274122
#define mac 50001

using namespace std;

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

vector<pair<int,int> > v[mac];
int  d[mac],fr[mac], viz[mac];
int n,m;
queue<int> q;

void citire()
{
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int x,y,z;
        fin>>x>>y>>z;
        v[x].push_back({y,z});
    }
}

int bellman(int sursa)
{
    for(int i=1;i<=n;i++)
       {
        viz[i]=0;
        fr[i]=0;
        d[i]=oo;
       }
    d[sursa]=0;
    q.push(sursa);
    fr[sursa]=1;
    while(!q.empty())
    {
        int curent=q.front();
        viz[curent]++;
        if(viz[curent]>=n) return 0;
        q.pop();
        fr[curent]=0;
        for(size_t i=0;i<v[curent].size();i++)
        {
            int vec,cot;
            vec=v[curent][i].first;
            cot=v[curent][i].second;
            if(d[curent]+cot < d[vec])
            {
                d[vec] = d[curent]+cot;
                if(!fr[vec])
                    {
                        q.push(vec);
                    }
            }
        }
    }
    return 1;
}

void afisare()
{
    if(bellman(1))
    {
        for(int i=2;i<=n;i++)
            fout<<d[i]<<" ";
    }
    else
      fout<<"Ciclu negativ!";
}

int main()
{
    citire();
    afisare();
    return 0;
}