Cod sursa(job #700729)

Utilizator avram_florinavram florin constantin avram_florin Data 1 martie 2012 11:44:16
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.91 kb
#include<fstream>
#include<cstdio>
#include<vector>
#include<queue>

using namespace std;

const int MaxN = 100001;

const char InFile[] = "bfs.in";
const char OutFile[] = "bfs.out";

int N,M,S,viz[MaxN];
vector<int> G[MaxN];
queue<int> Q;

void BFS()
{
	int nod;
	vector<int>::iterator it;
	for( nod = 1 ; nod <= N ; ++nod )
		viz[nod] = -1;
	viz[S] = 0;
	Q.push(S);
	while( !Q.empty() )
		{
			nod = Q.front();
			Q.pop();
			for( it = G[nod].begin() ; it != G[nod].end() ; ++it )
				if( viz[*it] == -1 )
					{
						Q.push(*it);
						viz[*it] = viz[nod] + 1;
					}
		}
}

int main()
{
	ifstream fin( InFile );
	ofstream fout( OutFile );
	fin >> N >> M >> S;
	int i,x,y;
	for( i = 0 ; i < M ; ++i )
		{
			fin >> x >> y;
			G[x].push_back(y);
		}
	BFS();
	for( i = 1 ; i <= N ; i++ )
		fout << viz[i] << ' ';
	fout << '\n';
	fin.close();
	fout.close();
	return 0;
}