Cod sursa(job #1548054)

Utilizator andrei_bB. Andrei andrei_b Data 10 decembrie 2015 13:11:49
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.8 kb
#include <fstream>
#include <queue>
#include <vector>

using namespace std;

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

vector <int> v[100005];
queue <int> q;
int n,m,a,b,c,dist[100005];


void bfs ( int p ){

    for ( int i=0 ; i<v[p].size() ; i++ ){
        if ( !dist[v[p][i]] && v[p][i]!=a ){
            dist[v[p][i]]=dist[p]+1;
            q.push(v[p][i]);
        }
    }

    q.pop();
    if ( !q.empty() )
        bfs(q.front());
}


int main()
{
    fin>>n>>m>>a;
    for ( int i=1 ; i<=m ; i++ ){
        fin>>c>>b;
        if ( c!=b )
            v[c].push_back(b);
    }

    q.push(a);
    bfs(a);

    for ( int i=1 ; i<=n ; i++ ){
        if ( dist[i]==0 && i!=a )
            fout<<"-1"<<' ';
        else
            fout<<dist[i]<<' ';
    }


}