Python/maths/find_max_recursion.py
Christian Clauss 1f8a21d727
Tighten up psf/black and flake8 ()
* Tighten up psf/black and flake8

* Fix some tests

* Fix some E741

* Fix some E741

* updating DIRECTORY.md

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
2020-05-22 08:10:11 +02:00

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790 B
Python

# Divide and Conquer algorithm
def find_max(nums, left, right):
"""
find max value in list
:param nums: contains elements
:param left: index of first element
:param right: index of last element
:return: max in nums
>>> nums = [1, 3, 5, 7, 9, 2, 4, 6, 8, 10]
>>> find_max(nums, 0, len(nums) - 1) == max(nums)
True
"""
if left == right:
return nums[left]
mid = (left + right) >> 1 # the middle
left_max = find_max(nums, left, mid) # find max in range[left, mid]
right_max = find_max(nums, mid + 1, right) # find max in range[mid + 1, right]
return left_max if left_max >= right_max else right_max
if __name__ == "__main__":
nums = [1, 3, 5, 7, 9, 2, 4, 6, 8, 10]
assert find_max(nums, 0, len(nums) - 1) == 10