Mean of Array After Removing Some Elements — LeetCode 1619 Python Solution

The problem

Given an integer array arr, return the mean of the remaining integers after removing the smallest 5% and the largest 5% of the elements. Answers within 10-5 of the actual answer will be considered accepted.

Example

Input

arr = [1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,3]

Output

2.00000

Explanation

After erasing the minimum and the maximum values of this array, all elements are equal to 2, so the mean is 2.

Python solution

class Solution:
    def trimMean(self, arr: List[int]) -> float:
        n = len(arr)
        start, end = int(n * 0.05), int(n * 0.95)
        arr.sort()
        t = arr[start:end]
        return round(sum(t) / len(t), 5)

Complexity

Pattern: Sorting

Spend O(n log n) once to buy an ordering that makes the rest of the problem trivial. LeetCode 1619. Mean of Array After Removing Some Elements is filed here because LeetCode tags it Sorting, which is the vocabulary this hub collects.

The sorting guide has the Python template for the pattern and the 401 LeetCode problems that use it.

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