1619. The mean value of the array after deleting some elements (C++)
1 topic description
Give you an integer array arr, please delete the minimum 5% of the number and the maximum 5% of the number, the average of the remaining numbers.
Results with a deviation of 10^-5 from the standard answer are regarded as correct results.
2 Example description
2.1 Example 2
Input: arr = [1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,3]
Output: 2.0000
Explanation: After deleting the largest and smallest elements in the array, all elements are equal to 2, so the average value is 2.
2.2 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: 4.0000
2.3 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: 4.777778
2.4 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
2.5 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
3 Problem solving tips
20 <= arr.length <= 1000
arr.length 是 20 的 倍数
0 <= arr[i] <= 10^5
4 Problem-solving ideas
Solve with violence.
5 Detailed source code (C++)
class Solution {
public:
double trimMean(vector<int>& arr) {
int n = arr.size() / 20 ;
double sum = 0 ;
sort( arr.begin() , arr.end() ) ;
for ( int i = n ; i < arr.size() - n ; i ++ )
{
sum = sum + arr[i] ;
}
return ( sum / ( arr.size() - 2 * n) ) ;
}
};