Binary Count Trailing Zeros
P
R
from math import log2
def binary_count_trailing_zeros(a: int) -> int:
"""
Take in 1 integer, return the number of trailing zeros in binary representation.
>>> binary_count_trailing_zeros(25)
0
>>> binary_count_trailing_zeros(36)
2
>>> binary_count_trailing_zeros(16)
4
>>> binary_count_trailing_zeros(58)
1
>>> binary_count_trailing_zeros(4294967296)
32
>>> binary_count_trailing_zeros(0)
Traceback (most recent call last):
...
ValueError: Trailing zeros for 0 are undefined
>>> binary_count_trailing_zeros(-10)
Traceback (most recent call last):
...
ValueError: Input value must be a positive integer
>>> binary_count_trailing_zeros(0.8)
Traceback (most recent call last):
...
TypeError: Input value must be an integer
>>> binary_count_trailing_zeros("0")
Traceback (most recent call last):
...
TypeError: Input value must be an integer
"""
# Type check
if not isinstance(a, int):
raise TypeError("Input value must be an integer")
# Edge case: zero
if a == 0:
raise ValueError("Trailing zeros for 0 are undefined")
# Negative numbers not allowed
if a < 0:
raise ValueError("Input value must be a positive integer")
# Core logic
return int(log2(a & -a))
if __name__ == "__main__":
import doctest
doctest.testmod()