Cod sursa(job #482014)

Utilizator claudiumihailClaudiu Mihail claudiumihail Data 2 septembrie 2010 13:11:51
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.92 kb
#include<fstream>
#include<iostream>
#include<vector>
#include<queue>
using namespace std;

int main()
{
	int n,m,s;
	fstream fin("bfs.in", fstream::in);
	fstream fout("bfs.out", fstream::out);
	vector< vector<int> > graph;
	vector<int> distances;
	queue<pair<int,int> > Q;
	fin>>n>>m>>s;
	graph.resize(n+1);
	distances.resize(n+1);
	for(int i=0; i<m; ++i)
	{
		int x,y;
		fin>>x>>y;
		graph[x].push_back(y);
	}

	for(int i=1; i<=n; ++i)
		distances[i]=-1;

	Q.push(make_pair(s,1));
	distances[s]=0;

	while(!Q.empty())
	{
		int node=Q.front().first;
		int dist=Q.front().second;
		Q.pop();
		for(unsigned int i=0; i<graph[node].size(); ++i)
		{
			if(distances[graph[node][i]]==-1)
			{
				distances[graph[node][i]]=dist;
				Q.push(make_pair(graph[node][i],dist+1));
			}
		}
	}

	for(int i=1; i<=n; ++i)
		fout<<distances[i]<<" ";
	fout<<endl;

	fin.close();
	fout.close();
	return 0;
}