Python/maths/find_min.py
Caeden Perelli-Harris fb1b939a89
Consolidate find_min and find_min recursive and find_max and find_max_recursive ()
* updating DIRECTORY.md

* refactor(min-max): Consolidate implementations

* updating DIRECTORY.md

* refactor(min-max): Append _iterative to func name

---------

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
2023-08-14 04:17:27 -07:00

88 lines
2.6 KiB
Python

from __future__ import annotations
def find_min_iterative(nums: list[int | float]) -> int | float:
"""
Find Minimum Number in a List
:param nums: contains elements
:return: min number in list
>>> for nums in ([3, 2, 1], [-3, -2, -1], [3, -3, 0], [3.0, 3.1, 2.9]):
... find_min_iterative(nums) == min(nums)
True
True
True
True
>>> find_min_iterative([0, 1, 2, 3, 4, 5, -3, 24, -56])
-56
>>> find_min_iterative([])
Traceback (most recent call last):
...
ValueError: find_min_iterative() arg is an empty sequence
"""
if len(nums) == 0:
raise ValueError("find_min_iterative() arg is an empty sequence")
min_num = nums[0]
for num in nums:
min_num = min(min_num, num)
return min_num
# Divide and Conquer algorithm
def find_min_recursive(nums: list[int | float], left: int, right: int) -> int | float:
"""
find min value in list
:param nums: contains elements
:param left: index of first element
:param right: index of last element
:return: min in nums
>>> for nums in ([3, 2, 1], [-3, -2, -1], [3, -3, 0], [3.0, 3.1, 2.9]):
... find_min_recursive(nums, 0, len(nums) - 1) == min(nums)
True
True
True
True
>>> nums = [1, 3, 5, 7, 9, 2, 4, 6, 8, 10]
>>> find_min_recursive(nums, 0, len(nums) - 1) == min(nums)
True
>>> find_min_recursive([], 0, 0)
Traceback (most recent call last):
...
ValueError: find_min_recursive() arg is an empty sequence
>>> find_min_recursive(nums, 0, len(nums)) == min(nums)
Traceback (most recent call last):
...
IndexError: list index out of range
>>> find_min_recursive(nums, -len(nums), -1) == min(nums)
True
>>> find_min_recursive(nums, -len(nums) - 1, -1) == min(nums)
Traceback (most recent call last):
...
IndexError: list index out of range
"""
if len(nums) == 0:
raise ValueError("find_min_recursive() arg is an empty sequence")
if (
left >= len(nums)
or left < -len(nums)
or right >= len(nums)
or right < -len(nums)
):
raise IndexError("list index out of range")
if left == right:
return nums[left]
mid = (left + right) >> 1 # the middle
left_min = find_min_recursive(nums, left, mid) # find min in range[left, mid]
right_min = find_min_recursive(
nums, mid + 1, right
) # find min in range[mid + 1, right]
return left_min if left_min <= right_min else right_min
if __name__ == "__main__":
import doctest
doctest.testmod(verbose=True)