19-02-19 traccia B

ALGOIT(A,x,y,z)
STZ=STY=STA=STVAL=LAST=NIL
cx=x ; cy =y
while(cx <= cy || sty!=NIL)do
	if(cx<=cy)then
		val=0
		z=cx+cy/2
		if(A[z]=k)then
			val=1
		stval=push(stval,val)
		stz=push(stz,z)
		sty=push(sty,cy)
		cy=z-1
	else
		val=top(stval); z=top(stz); cy=top(sty)
		if(last!=cy)then
			a=val
			sta=push(sta,a)
			if(a>val)then
				cx=z+1 //preparo prossima chiamata
			else
				b=a+val
				val=val+a+b
				last=cx
				cx=cy+1
				pop(vari)
		else
			b=val
			val=val+top(sta)+b
			last=cx
			cx=cy+1
			val=ret
			pop(vari)

	return val