Cod sursa(job #686646)

Utilizator DianaDDiana Dr. DianaD Data 21 februarie 2012 19:18:12
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.94 kb
#include <fstream>
#include <queue>
#include <vector>
#include <iostream>

using namespace std;

ifstream in ("bfs.in");
ofstream out ("bfs.out");

int d[100020], S,  M, N,x,y;
queue <int> q;
vector<int> a[100020];



void citire ()
{
    int x,y;
    for (int i=1;i<=M;i++)
    {
        in>>x>>y;
        a[x].push_back(y);
    }
}

void bfs(int S)
{
    for ( int i=1; i<=N ; i++)
    {
        d[i]=-1;
    }
    q.push (S);
    d[S] = 0;
    while (!q.empty())
    {
        x = q.front ();
        q.pop ();
        for (int i=0; i<a[x].size() ; i++)
        {
            y = a[x][i];
            if (d[y] == -1)
            {
                q.push (y);
                d [y] = 1 + d [x];
            }
        }
    }
}

int main ()
{
    //cout << "aaaa\n";
    in>>N>>M>>S;
    citire ();
    bfs (S);
    for (int i=1; i<=N ; i++)
    {
        out<<d[i]<<" ";
    }
    return 0;
}