Python/maths/find_min_recursion.py
Du YuanChao 83c104e839 Divide and Conquer (#1308)
Thanks for your persistence!
2019-10-18 06:20:36 +02:00

26 lines
789 B
Python

# Divide and Conquer algorithm
def find_min(nums, left, right):
"""
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
>>> nums = [1, 3, 5, 7, 9, 2, 4, 6, 8, 10]
>>> find_min(nums, 0, len(nums) - 1) == min(nums)
True
"""
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__":
nums = [1, 3, 5, 7, 9, 2, 4, 6, 8, 10]
assert find_min(nums, 0, len(nums) - 1) == 1