Cod sursa(job #604442)

Utilizator a_h1926Heidelbacher Andrei a_h1926 Data 22 iulie 2011 14:21:55
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.08 kb
#include <iostream>
#include <vector>
#include <queue>

#define NMax 100005

using namespace std;

vector <int> G[NMax];
int N, L[NMax], S;
bool Viz[NMax];
queue <int> Q;

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])
        {
            L[i]=-1;
        }
        printf ("%d ", L[i]);
    }
}

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

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