Cod sursa(job #250905)

Utilizator moonbeamElma Moonbeam moonbeam Data 1 februarie 2009 11:13:52
Problema BFS - Parcurgere in latime Scor 80
Compilator cpp Status done
Runda Arhiva educationala Marime 0.83 kb
#include<stdio.h>
#define N 100000
#define M 1000000
int *a[N],d[N],x[M],y[M],n,m,viz[N],s;
void bfs(int x0)
{
	int coada[N],p,u,x,y;
	for (int i=1; i<=n; ++i) d[i]=-1;
	p=u=0;
	coada[u++]=x0;
	viz[x0]=1;
	d[x0]=0;
	while (p!=u)
	{
		x=coada[p++];
		for (int i=1; i<=a[x][0]; ++i)
		{
			y=a[x][i];
			if (!viz[y])
			{
				coada[u++]=y;
				viz[y]=1;
				d[y]=1+d[x];
			}
		}
	}
	for(int i=1; i<=n; ++i)
		printf("%d ",d[i]);
}
void citire()
{
	freopen("bfs.in","r",stdin);
	freopen("bfs.out","w",stdout);
	scanf("%d%d%d",&n,&m,&s);
	for (int i=1; i<=m; ++i)
	{
		scanf("%d%d",&x[i],&y[i]);
		++d[x[i]];
	}
	for (int i=1; i<=n; ++i)
	{
		a[i]= new int [1+d[i]];
		a[i][0]=0;
	}
	for (int i=1; i<=m; ++i)
	{
		a[x[i]][++a[x[i]][0]]=y[i];
	}
	bfs(s);
}

int main()
{
	citire();
	return 0;
}