python 刷题：跳台阶

方案一

# -*- coding:utf-8 -*-
class Solution:
def jumpFloor(self, number):
# write code here
if number < 1:
return 0
elif number == 1:
return 1
elif number == 2:
return 2
else:
a = 1
b = 2
c = 3
for i in range(3, number + 1):
c = a + b
a = b
b = c
return c