# 1619. Mean of Array After Removing Some Elements

## Description

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 1:

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.


Example 2:

Input: arr = [6,2,7,5,1,2,0,3,10,2,5,0,5,5,0,8,7,6,8,0]
Output: 4.00000


Example 3:

Input: arr = [6,0,7,0,7,5,7,8,3,4,0,7,8,1,6,8,1,1,2,4,8,1,9,5,4,3,8,5,10,8,6,6,1,0,6,10,8,2,3,4]
Output: 4.77778


Constraints:

• 20 <= arr.length <= 1000
• arr.length is a multiple of 20.
• 0 <= arr[i] <= 105

## Solutions

• class Solution {
public double trimMean(int[] arr) {
Arrays.sort(arr);
int n = arr.length;
double s = 0;
for (int start = (int) (n * 0.05), i = start; i < n - start; ++i) {
s += arr[i];
}
return s / (n * 0.9);
}
}

• class Solution {
public:
double trimMean(vector<int>& arr) {
sort(arr.begin(), arr.end());
int n = arr.size();
double s = 0;
for (int start = (int) (n * 0.05), i = start; i < n - start; ++i)
s += arr[i];
return s / (n * 0.9);
}
};

• 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)


• func trimMean(arr []int) float64 {
sort.Ints(arr)
n := len(arr)
sum := 0.0
for i := n / 20; i < n-n/20; i++ {
sum += float64(arr[i])
}
return sum / (float64(n) * 0.9)
}

• function trimMean(arr: number[]): number {
arr.sort((a, b) => a - b);
let n = arr.length,
rmLen = n * 0.05;
let sum = 0;
for (let i = rmLen; i < n - rmLen; i++) {
sum += arr[i];
}
return sum / (n * 0.9);
}


• impl Solution {
pub fn trim_mean(mut arr: Vec<i32>) -> f64 {
arr.sort();
let n = arr.len();
let count = ((n as f64) * 0.05).floor() as usize;
let mut sum = 0;
for i in count..n - count {
sum += arr[i];
}
(sum as f64) / ((n as f64) * 0.9)
}
}