yığıt ile desimalden fibonacciye dönüşüm. (2014 final soru 3)

yigitfib.py

class Stack:
    def __init__(self):
        self.alist=[]
    def pop(self):
        return self.alist.pop()
    def push(self,a):
        self.alist.append(a)
    def show(self):
        return self.alist
    def peek(self):
        return self.alist[len(self.alist)-1]
    def isempty(self):
        return len(self.alist)==0
    def size(self):
        return len(self.alist)


s=Stack()
def dec2fib(sayi):
    s.push(1)
    s.push(1)
    if sayi==1 or sayi==2:
        return 1
    for i in range(sayi-2):
        a=s.pop()
        b=s.peek()
        s.push(a)
        s.push(a+b)
    return s.pop()

print (dec2fib(7))