Find Min Recursion

from __future__ import annotations


# Divide and Conquer algorithm
def find_min(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(nums, 0, len(nums) - 1) == min(nums)
    True
    True
    True
    True
    >>> nums = [1, 3, 5, 7, 9, 2, 4, 6, 8, 10]
    >>> find_min(nums, 0, len(nums) - 1) == min(nums)
    True
    >>> find_min([], 0, 0)
    Traceback (most recent call last):
        ...
    ValueError: find_min() arg is an empty sequence
    >>> find_min(nums, 0, len(nums)) == min(nums)
    Traceback (most recent call last):
        ...
    IndexError: list index out of range
    >>> find_min(nums, -len(nums), -1) == min(nums)
    True
    >>> find_min(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() 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(nums, left, mid)  # find min in range[left, mid]
    right_min = find_min(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)
Algerlogo

Β© Alger 2022

About us

We are a group of programmers helping each other build new things, whether it be writing complex encryption programs, or simple ciphers. Our goal is to work together to document and model beautiful, helpful and interesting algorithms using code. We are an open-source community - anyone can contribute. We check each other's work, communicate and collaborate to solve problems. We strive to be welcoming, respectful, yet make sure that our code follows the latest programming guidelines.