Cod sursa(job #796408)

Utilizator gherghe94Andrei Gherghelau gherghe94 Data 11 octombrie 2012 13:45:59
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.27 kb
#include <cstdio>
#include <vector>
#include <queue>
#define Nmax 100005
using namespace std;

queue <int> Q;
vector <int> V[Nmax];

int n,m,s;
int viz[Nmax];///
int c[Nmax];///caii
void Read()
{
    freopen("bfs.in","r",stdin);
    scanf("%d %d %d",&n,&m,&s);
    for(int i = 0 ; i < m; i++)
    {
        int x,y;
        scanf("%d %d",&x,&y);
        V[x].push_back(y);///orientat
    }
}
void BFS(int s)
{
    for(int i = 0; i <= Nmax; i++)
        c[i] = -1;///setez val -1
    c[s] = 0;///in nod pun 0 caci nu voi avea drum la inceput din el in el
    viz[s] = 1;///vizitez
    Q.push(s);
    while(!Q.empty())
    {
        int p = Q.front();///iau primul nod din coada
        for(int j = 0 ; j < V[p].size();j++)
        {
            if(!viz[V[p][j]])
            {
                viz[V[p][j]] = 1;///vizitez nodul
                c[V[p][j]] = 1+c[p];///adaug un arc in + fata de ce era
                Q.push(V[p][j]);///il bag in coada pentru a gasi urmatoarea valoare
            }
        }
        Q.pop();///elimin nodul
    }
}
void afisare()
{
    freopen("bfs.out","w",stdout);
    for(int i = 1; i<=n;i++)
    {
        printf("%d ",c[i]);
    }
}
int main()
{
    Read();
    BFS(s);
    afisare();

    return 0;
}