Cod sursa(job #367914)

Utilizator dead_knightTitei Paul Adrian dead_knight Data 23 noiembrie 2009 18:48:20
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.86 kb
#include<fstream>
#include<cstdlib>
using namespace std;
#define MAX 100001
struct nod{int info;
        nod *next;};
nod * a[MAX];
int n,d[MAX],s;
void read()
{
	ifstream fin("bfs.in");
	int m;
	fin>>n>>m>>s;
	for(int i=1;i<=n;i++)
	    a[i]=NULL,d[i]=-1;
	for(;m;m--)
	{
		int i,j;
		fin>>i>>j;
		nod *p=new nod;
		p->info=j;
		p->next=a[i];
		a[i]=p;
	}
}
void bfs()
{
	int k;
	nod *st,*dr;
	st=dr=new nod;
	dr->info=s;
	dr->next=NULL;
	d[s]=0;
	while(st)
	{
		k=st->info;
		for(nod *p=a[k];p;p=p->next)
		    if(d[p->info]==-1)
			   {
				   nod *q=new nod;
				   q->info=p->info;
				   q->next=NULL;
				   dr->next=q;
				   dr=q;
				   d[p->info]=d[k]+1;
				 }
	 nod *t=st;
	 st=st->next;
	 delete t;
   }
}

void write(){
	ofstream fout("bfs.out");
	for(int i=1;i<=n;i++)
	    fout<<d[i]<<" ";
	fout.close();
}

int main()
{
	read();
	bfs();
	write();
    return 0;
}