Cod sursa(job #604361)

Utilizator a_h1926Heidelbacher Andrei a_h1926 Data 21 iulie 2011 22:33:23
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.11 kb
#include <iostream>
#include <vector>
#include <queue>

#define NMax 100005

using namespace std;

vector <int> G[NMax];
int N, D[NMax], S;
bool Viz[NMax];

void Read ()
{
    freopen ("bfs.in", "r", stdin);
    int M;
    scanf ("%d %d %d", &N, &M, &S);
    for (; M>0; --M)
    {
        int X, Y;
        scanf ("%d %d", &X, &Y);
        G[X].push_back (Y);
    }
}

void Print ()
{
    freopen ("bfs.out", "w", stdout);
    for (int i=1; i<=N; ++i)
    {
        if (!Viz[i])
        {
            D[i]=-1;
        }
        printf ("%d ", D[i]);
    }
    printf ("\n");
}

void BFS (int Start)
{
    queue <int> Q;
    Viz[Start]=1;
    Q.push (Start);
    while (!Q.empty ())
    {
        int X=Q.front ();
        Q.pop ();
        Viz[X]=true;
        for (unsigned i=0; i<G[X].size (); ++i)
        {
            int V=G[X][i];
            if (!Viz[V])
            {
                D[V]=D[X]+1;
                Viz[V]=true;
                Q.push (V);
            }
        }
    }
}

int main()
{
    Read ();
    BFS (S);
    Print ();
    return 0;
}