1619. Mean of Array After Removing Some Elements #

题目 #

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

Example 4:

Input: arr = [9,7,8,7,7,8,4,4,6,8,8,7,6,8,8,9,2,6,0,0,1,10,8,6,3,3,5,1,10,9,0,7,10,0,10,4,1,10,6,9,3,6,0,0,2,7,0,6,7,2,9,7,7,3,0,1,6,1,10,3]
Output: 5.27778

Example 5:

Input: arr = [4,8,4,10,0,7,1,3,7,8,8,3,4,1,6,2,1,1,8,0,9,8,0,3,9,10,3,10,1,10,7,3,2,1,4,9,10,7,6,4,0,8,5,1,2,1,6,2,5,0,7,10,9,10,3,7,10,5,8,5,7,6,7,6,10,9,5,10,5,5,7,2,10,7,7,8,2,0,1,1]
Output: 5.29167

Constraints:

• 20 <= arr.length <= 1000
• arr.length is a multiple of 20.
• 0 <= arr[i] <= 10^5

题目大意 #

给你一个整数数组 arr ，请你删除最小 5% 的数字和最大 5% 的数字后，剩余数字的平均值。与 标准答案 误差在 10-5 的结果都被视为正确结果。

解题思路 #

• 简单题。先将数组排序，然后累加中间 90% 的元素，最后计算平均值。

代码 #

package leetcode

import "sort"

func trimMean(arr []int) float64 {
	sort.Ints(arr)
	n, sum := len(arr), 0
	for i := n / 20; i < n-(n/20); i++ {
		sum += arr[i]
	}
	return float64(sum) / float64((n - (n / 10)))
}