mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-24 05:21:09 +00:00
61eedc16c3
* refactor: Fix matrix display deprecation * refactor: Remove useless `print` and `pass` statements * revert: Replace broken doctests * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci * revert: Fix failing doctests * chore: Satisfy pre-commit Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
60 lines
1.6 KiB
Python
60 lines
1.6 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 __future__ import annotations
|
|
|
|
|
|
def binary_search(a_list: list[int], item: int) -> bool:
|
|
"""
|
|
>>> test_list = [0, 1, 2, 8, 13, 17, 19, 32, 42]
|
|
>>> binary_search(test_list, 3)
|
|
False
|
|
>>> binary_search(test_list, 13)
|
|
True
|
|
>>> binary_search([4, 4, 5, 6, 7], 4)
|
|
True
|
|
>>> binary_search([4, 4, 5, 6, 7], -10)
|
|
False
|
|
>>> binary_search([-18, 2], -18)
|
|
True
|
|
>>> binary_search([5], 5)
|
|
True
|
|
>>> binary_search(['a', 'c', 'd'], 'c')
|
|
True
|
|
>>> binary_search(['a', 'c', 'd'], 'f')
|
|
False
|
|
>>> binary_search([], 1)
|
|
False
|
|
>>> binary_search([-.1, .1 , .8], .1)
|
|
True
|
|
>>> binary_search(range(-5000, 5000, 10), 80)
|
|
True
|
|
>>> binary_search(range(-5000, 5000, 10), 1255)
|
|
False
|
|
>>> binary_search(range(0, 10000, 5), 2)
|
|
False
|
|
"""
|
|
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}")
|