28-06-17 (traduzione RIC-IT)
ALGO(T,a,b)
ST=LAST=NIL
CT=T
while(ct!=NIL || st!=NIL)do
	if(ct!=NIL)then
		if(ct->key<a || st->key>b)then
			st=push(st,ct)
			if(ct->key<a)then
				ct=ct->sx
			else if(ct->key>b)then
				ct=ct->dx
			else
				ct=ct->sx
	else
		ct=top(st)
		if(ct->key<a)then
			ct->sx=val
			last=ct
			ct=NIL
			pop(st)
		else if(ct->key>b)then
			ct->dx=val
			last=ct
			ct=NIL
			pop(st)
		else
			if(last!=ct->dx && ct->dx!=NIL)then
				ct->sx=val
				ct=ct->dx
			else
				if(ct->dx = NIL)then
					ct->sx=val
					ct->dx=NIL
					ct=cancellaradice(ct)
				else
					ct->dx=val
					ct=cancellaradice(ct)
			last=ct
			ct=NIL
			pop(st)
	return ct