Cod sursa(job #676243)

Utilizator lucian666Vasilut Lucian lucian666 Data 8 februarie 2012 21:19:13
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.84 kb
#include<fstream>
#include<queue>
#include<vector>
#define INF 0X3f3f3f
#define N 100001
using namespace std;
ofstream fout("bfs.out");
vector<int>G[N];
queue<int>Q;
vector<int>::iterator I;
int n,s,d[N],v[N];
void BFS (int start);
void citire();
int main()
{
	citire();
	BFS(s);
	for(int i=1;i<=n;i++)
		if(d[i]==INF)
		fout<<-1<<" ";
		else
			fout<<d[i]<<" ";
		return 0;
}
void citire()
{
	ifstream fin("bfs.in");
	int m;
	fin>>n>>m>>s;
	int x,y;
	for(int i=1;i<=m;i++)
	{
		fin>>x>>y;
	G[x].push_back(y);
}
}
void BFS(int start)
{
	for(int i=1;i<=n;i++)
	{	d[i]=INF;}
	v[start]=1;
	d[start]=0;
	Q.push(start);
		while(!Q.empty())
		{
			int k=Q.front();
				for(I=G[k].begin();I<G[k].end();I++)
					if(v[*I]==0)
					{
						Q.push(*I);
						v[*I]=1;
						d[*I]=d[k]+1;
					}
					Q.pop();
		}
}