#! /usr/bin/python
# -*- coding:utf-8 -*-
"""
an interesting topic Fibonacci sequence
"""
#the method we know how to solve this issue ----recursion
def fib(n):
if n ==1 or n ==2 :
return 1
else:
return fib(n-1)+ fib(n-2)
n = 10
print "Fibonacci sequence value of %d is : " % n,fib(n)
# 有点意思
def fibv2(n):
a,b =1,1
for i in range(n-1): # if n = 10 then 10 -1 = 9 range(9) ,recursion 9 times
a,b= b,a+b # ???
print 'a=',a,'b=',b
return a
print fibv2(10)
"""
Fibonacci sequence value of 10 : 55
a= 1 b= 2
a= 2 b= 3
a= 3 b= 5
a= 5 b= 8
a= 8 b= 13
a= 13 b= 21
a= 21 b= 34
a= 34 b= 55
a= 55 b= 89
55
"""