Python/dynamic_programming/climbing_stairs.py
giladwo 00dfad9d20
Simplify climbing stairs and use constant memory ()
* Simplify climbing stairs and use constant memory

* number_of_steps

Co-authored-by: Christian Clauss <cclauss@me.com>
2022-10-30 10:59:10 +01:00

43 lines
1.1 KiB
Python

#!/usr/bin/env python3
def climb_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
"""
assert (
isinstance(number_of_steps, int) and number_of_steps > 0
), f"number_of_steps needs to be positive integer, your input {number_of_steps}"
if number_of_steps == 1:
return 1
previous, current = 1, 1
for _ in range(number_of_steps - 1):
current, previous = current + previous, current
return current
if __name__ == "__main__":
import doctest
doctest.testmod()