Cod sursa(job #1193666)

Utilizator AdrianaMAdriana Moisil AdrianaM Data 1 iunie 2014 13:53:38
Problema BFS - Parcurgere in latime Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.06 kb
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

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

int n, m, s;
vector<vector<int> > c;
vector<int> d;
queue<int> q;
vector<bool> ok;

int main()
{
    is >> n >> m >> s;
    c.resize(n + 1);
    d.resize(n + 1);
    ok.resize(n + 1);
    int x, y;
    for ( int i = 1; i <= m; ++i )
    {
        is >> x >> y;
        if ( x != y )
            c[x].push_back(y);
    }
    q.push(s);
    while ( !q.empty() )
    {
        x = q.front();
        q.pop();
        for ( vector<int>::iterator it = c[x].begin(); it != c[x].end(); ++it )
        {
            if ( *it == s )
                continue;
            d[*it] = d[x] + 1;
            if ( !ok[*it] )
            {
                q.push(*it);
                ok[*it] = true;
            }
        }
    }
    for ( int i = 1; i <= n; ++i )
    {
        if ( i != s && !d[i] )
            os << "-1 ";
        else
            os << d[i] << " ";
    }
    is.close();
    os.close();
    return 0;
}