"""

Trimmed Mean

Compute the mean of an array after discarding a given percentage of the

highest and lowest values. Useful for robust averaging in scoring systems.

Reference: https://en.wikipedia.org/wiki/Truncated_mean

Complexity:

Time: O(n log n) due to sorting

Space: O(n) for the trimmed copy

"""

from __future__ import annotations

def trimmean(array: list[float], percentage: float) -> float:

"""Calculate the trimmed mean of an array.

Discards the top and bottom halves of the given percentage before

computing the arithmetic mean.

Args:

array: List of numeric values.

percentage: Total percentage to trim (split equally between

top and bottom). E.g., 20 trims the top 10% and bottom 10%.

Returns:

The trimmed arithmetic mean.

Examples:

>>> trimmean([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 20)

5.5

"""

ratio = percentage / 200

array.sort()

trim_count = int(len(array) * ratio)

trimmed = array[trim_count : len(array) - trim_count]

total = 0

for value in trimmed:

total += value

return total / len(trimmed)