mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-10-05 21:29:29 +00:00
47bf3f58e0
* fix validation condition and add tests
* updating DIRECTORY.md
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
52 lines
1.4 KiB
Python
52 lines
1.4 KiB
Python
# Reference: https://www.geeksforgeeks.org/position-of-rightmost-set-bit/
|
|
|
|
|
|
def get_index_of_rightmost_set_bit(number: int) -> int:
|
|
"""
|
|
Take in a positive integer 'number'.
|
|
Returns the zero-based index of first set bit in that 'number' from right.
|
|
Returns -1, If no set bit found.
|
|
|
|
>>> get_index_of_rightmost_set_bit(0)
|
|
-1
|
|
>>> get_index_of_rightmost_set_bit(5)
|
|
0
|
|
>>> get_index_of_rightmost_set_bit(36)
|
|
2
|
|
>>> get_index_of_rightmost_set_bit(8)
|
|
3
|
|
>>> get_index_of_rightmost_set_bit(-18)
|
|
Traceback (most recent call last):
|
|
...
|
|
ValueError: Input must be a non-negative integer
|
|
>>> get_index_of_rightmost_set_bit('test')
|
|
Traceback (most recent call last):
|
|
...
|
|
ValueError: Input must be a non-negative integer
|
|
>>> get_index_of_rightmost_set_bit(1.25)
|
|
Traceback (most recent call last):
|
|
...
|
|
ValueError: Input must be a non-negative integer
|
|
"""
|
|
|
|
if not isinstance(number, int) or number < 0:
|
|
raise ValueError("Input must be a non-negative integer")
|
|
|
|
intermediate = number & ~(number - 1)
|
|
index = 0
|
|
while intermediate:
|
|
intermediate >>= 1
|
|
index += 1
|
|
return index - 1
|
|
|
|
|
|
if __name__ == "__main__":
|
|
"""
|
|
Finding the index of rightmost set bit has some very peculiar use-cases,
|
|
especially in finding missing or/and repeating numbers in a list of
|
|
positive integers.
|
|
"""
|
|
import doctest
|
|
|
|
doctest.testmod(verbose=True)
|