Cod sursa(job #767702)

Utilizator alexandru93moraru alexandru sebastian alexandru93 Data 14 iulie 2012 14:15:19
Problema BFS - Parcurgere in latime Scor 70
Compilator cpp Status done
Runda Arhiva educationala Marime 0.76 kb
#include <fstream>
#include <vector>
#include <queue>
#define maxn 100010
using namespace std;

long N,M,S;
long Viz[maxn],Cost[maxn];
queue <long> Q;
vector <long> V[maxn];

void BFS(long nod){
	Q.push(nod);
	Viz[nod]=1;
	while(!Q.empty()){
		nod=Q.front();
		Q.pop();
		for(vector<long>::iterator it=V[nod].begin();it!=V[nod].end();++it)
			if(Viz[*it]==-1){
				Q.push(*it);
				Viz[*it]=1;
				Cost[*it]=Cost[nod]+1;
			}
	}
}   

int main(){
    ifstream f("bfs.in");
	ofstream g("bfs.out");
	
	long x,y;
	f>>N>>M>>S;
	
	for(long i=1;i<=M;i++){
		f>>x>>y;
		V[x].push_back(y);
		Viz[i]=-1;
	}
	
	BFS(S);

	for(long i=1;i<=N;i++)
		if(Cost[i]==0&&i!=S)
			g<<-1<<' ';
		else
		g<<Cost[i]<<' ';
	g<<'\n';
	g.close();
	return 0;
}