ALGOIT(T,L)
STL=STX=STP=LAST=NIL
CT=T
while(ct!=NIl || st!=NIL)do
	if(ct!=NIL)then
		p=ct->k%2
		stp=push(stp,cp)
		st=push(st,ct)
		ct=ct->dx
	else
		ct=top(st); cp=top(stp)
		if(last!=ct->sx && ct->sx!=NIL)then
			Ld=val
			if(p=0)then
				x=new_node(ct->k)
				stx=push(stx,x)
				stl=push(stl,l)
				ct=ct->sx
				L=x
			else
				ct=ct->sx
				L=LD
		else
			if(ct->sx=NIL)then
				Ld=val
				if(p=0)then
					x=new_node(ct->k)
					L=NIL
					x->next=LD
					+ uscita algo
				else
					L=NIL
					+ uscita algo
			else
				if(p=0)then
					L=val
					top(stx)->next=Ld
					+ uscita algo
				else
					L=val
					+ uscita algo