climbing_stairs.py

#!/usr/bin/env python3


defclimb_stairs(number_of_steps: int) ->int:
"""
 LeetCdoe No.70: Climbing Stairs
 Distinct ways to climb a number_of_steps staircase where each time you can either
 climb 1 or 2 steps.

 Args:
 number_of_steps: number of steps on the staircase

 Returns:
 Distinct ways to climb a number_of_steps staircase

 Raises:
 AssertionError: number_of_steps not positive integer

 >>> climb_stairs(3)
 3
 >>> climb_stairs(1)
 1
 >>> climb_stairs(-7) # doctest: +ELLIPSIS
 Traceback (most recent call last):
 ...
 AssertionError: number_of_steps needs to be positive integer, your input -7
 """
assertisinstance(number_of_steps, int) andnumber_of_steps>0, (
f"number_of_steps needs to be positive integer, your input {number_of_steps}"
 )
ifnumber_of_steps==1:
return1
previous, current=1, 1
for_inrange(number_of_steps-1):
current, previous=current+previous, current
returncurrent


if__name__=="__main__":
importdoctest

doctest.testmod()