Cod sursa(job #672914)

Utilizator BitOneSAlexandru BitOne Data 3 februarie 2012 14:04:21
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.69 kb
#include <queue>
#include <vector>
#include <fstream>
#include <cstdlib>
#define N_MAX 100011
#define oo 1<<30

using namespace std;

int d[N_MAX];
queue< int > Q;
vector< int > G[N_MAX];
vector< int >::const_iterator it, iend;

int main()
{
	int N, M, S, x, y, i;
	ifstream in( "bfs.in" );
	ofstream out( "bfs.out" );
	
	for( in>>N>>M>>S; M; --M )
	{
		in>>x>>y;
		G[x].push_back( y );
	}
	for( i=1; i <= N; ++i )
		d[i]=-1;
	d[S]=0;
	for( Q.push(S); !Q.empty(); Q.pop() )
	{
		x=Q.front();
		for( it=G[x].begin(), iend=G[x].end(); it < iend; ++it )
			if( -1 == d[*it] )
			{
				d[*it]=d[x]+1;
				Q.push( *it );
			}
	}
	for( i=1; i <= N; ++i )
		out<<d[i]<<' ';
	out<<'\n';
	
	return EXIT_SUCCESS;
}