mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-12-18 09:10:16 +00:00
dc415ec14a
* double linear search recursion
* fixup! Format Python code with psf/black push
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
54 lines
1.5 KiB
Python
54 lines
1.5 KiB
Python
"""
|
|
Pure Python implementation of a binary search algorithm.
|
|
|
|
For doctests run following command:
|
|
python3 -m doctest -v simple_binary_search.py
|
|
|
|
For manual testing run:
|
|
python3 simple_binary_search.py
|
|
"""
|
|
from typing import List
|
|
|
|
|
|
def binary_search(a_list: List[int], item: int) -> bool:
|
|
"""
|
|
>>> test_list = [0, 1, 2, 8, 13, 17, 19, 32, 42]
|
|
>>> print(binary_search(test_list, 3))
|
|
False
|
|
>>> print(binary_search(test_list, 13))
|
|
True
|
|
>>> print(binary_search([4, 4, 5, 6, 7], 4))
|
|
True
|
|
>>> print(binary_search([4, 4, 5, 6, 7], -10))
|
|
False
|
|
>>> print(binary_search([-18, 2], -18))
|
|
True
|
|
>>> print(binary_search([5], 5))
|
|
True
|
|
>>> print(binary_search(['a', 'c', 'd'], 'c'))
|
|
True
|
|
>>> print(binary_search(['a', 'c', 'd'], 'f'))
|
|
False
|
|
>>> print(binary_search([], 1))
|
|
False
|
|
>>> print(binary_search([.1, .4 , -.1], .1))
|
|
True
|
|
"""
|
|
if len(a_list) == 0:
|
|
return False
|
|
midpoint = len(a_list) // 2
|
|
if a_list[midpoint] == item:
|
|
return True
|
|
if item < a_list[midpoint]:
|
|
return binary_search(a_list[:midpoint], item)
|
|
else:
|
|
return binary_search(a_list[midpoint + 1 :], item)
|
|
|
|
|
|
if __name__ == "__main__":
|
|
user_input = input("Enter numbers separated by comma:\n").strip()
|
|
sequence = [int(item.strip()) for item in user_input.split(",")]
|
|
target = int(input("Enter the number to be found in the list:\n").strip())
|
|
not_str = "" if binary_search(sequence, target) else "not "
|
|
print(f"{target} was {not_str}found in {sequence}")
|