Cod sursa(job #2365244)

Utilizator zagnatanaAna Zagnat zagnatana Data 4 martie 2019 12:40:12
Problema Algoritmul Bellman-Ford Scor 90
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.6 kb
#include <fstream>
#include <queue>
#include <vector>
#define NMAX 50002
#define INF 500000000

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

int n, m, start=1;
struct varf{int x; int c;};
vector <varf> G[NMAX];
int cmin[NMAX];/// cmin[x]= costul drimului de cost minim de la start la x
int nr[NMAX];/// de cate ori a fost actualizat costul druului de la start la x
int d[NMAX];
queue<int> C;


void citire();
bool bellman_ford();
void afisare();

int main()
{
    int i;
    citire();
    bellman_ford();
    if(!bellman_ford())
        fout<<"Ciclu negativ!";
        else
            for(i=2; i<=n; i++)
                if(cmin[i]==INF) fout<<-1<<' ';
                    else
                        fout<<cmin[i]<<' ';
    return 0;
}
void citire()
{int i,j,c, k;
varf aux;
fin>>n>>m;
for(k=0; k<m; k++)
   {
       fin>>i>>j>>c;
       aux.x=j; aux.c=c;
       G[i].push_back(aux);
   }
   //initializez

}
bool bellman_ford()
///returnam 0 daca nu exista sol. 1 daca exista
{
    ///intializare
    int i, vf;
    for(i=1; i<=n ;i++)
        cmin[i]=INF;
    cmin[start]=0;
    C.push(start);
    while(!C.empty())
    {
        vf=C.front();
        C.pop();
        ///parcurg lista de adiacenta lui vf
        for(i=0; i<G[vf].size(); i++)
            if(cmin[G[vf][i].x]>cmin[vf]+G[vf][i].c)
            {
                cmin[G[vf][i].x]=cmin[vf]+G[vf][i].c;
                nr[G[vf][i].x]++;
                if(nr[G[vf][i].x]==n) return 0;
                C.push(G[vf][i].x);
            }
    }
return 1;
}