Cod sursa(job #1108229)

Utilizator Athena99Anghel Anca Athena99 Data 15 februarie 2014 15:06:16
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.88 kb
#include <fstream>
#include <queue>
#include <vector>

using namespace std;

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

const int nmax= 100000;

int d[nmax+1];
vector <int> v[nmax+1];

void bfs( int x ) {
    d[x]= 0;
    queue <int> q;
    q.push(x);

    while ( !q.empty() ) {
        int x= q.front();
        q.pop();

        for ( vector <int>::iterator it= v[x].begin(); it!=v[x].end(); ++it ) {
            if ( d[*it]==-1 ) {
                d[*it]= d[x]+1;
                q.push(*it);
            }
        }
    }

}

int main(  ) {
    int n, m, s;
    fin>>n>>m>>s;
    for ( ; m; --m ) {
        int x, y;
        fin>>x>>y;
        v[x].push_back(y);
    }

    for ( int i= 1; i<=n; ++i ) {
        d[i]= -1;
    }
    bfs(s);

    for ( int i= 1; i<=n; ++i ) {
        fout<<d[i]<<" ";
    }
    fout<<"\n";

    return 0;
}