Cod sursa(job #1017808)

Utilizator pulseOvidiu Giorgi pulse Data 28 octombrie 2013 15:40:22
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.85 kb
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

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

const int NMAX=100002;
vector <int> a[NMAX];
queue <int> q;
int n,m,s,cost[NMAX];
bool used[NMAX];

void read ()
{
	fin>>n>>m>>s;
	for (int i=1, nod1, nod2; i<=m; ++i)
	{
		fin>>nod1>>nod2;
		a[nod1].push_back(nod2);
	}

}

void BFS ()
{
	q.push(s);
	cost[s]=0;
	used[s]=true;
	while (!q.empty())
	{
		int val=q.front();
		q.pop();
		for (int i=0; i<a[val].size(); ++i)
		{
			if (!used[a[val][i]])
			{
				used[a[val][i]]=true;
				cost[a[val][i]]=cost[val]+1;
				q.push(a[val][i]);
			}
		}
	}
	for (int i=1; i<=n; ++i)
	{
		if (used[i])
			fout<<cost[i]<<" ";
		else
			fout<<"-1 ";
	}
	fout<<"\n";
}

int main ()
{
	read ();
	BFS ();
	fin.close(); fout.close();
	return 0;
}