选择n个元素，使其均值最大

给定2 * n个元素的数组，任务是构造和打印n个元素的数组，以使新数组的均值最大。这里n是偶数。

例子：

Input: arr[] = {3, 1, 2, 3, 8, 6}
Output: 3 6 8

Input: arr[] = {3, 2, 3, 8}
Output: 3 8

方法：数组的均值是同一数组的元素的平均值，即(∑arr [i])/ n 。因此，为了使数组的平均值最大，请从数组中选择最大的n个元素，这可以通过首先对数组进行排序，然后从最大值开始选择元素来完成。

下面是上述方法的实现：

C++

// C++ implementation of the approach
#include 
using namespace std;
  
// Utility function to print the contents
// of an array
void printArray(int arr[], int n)
{
    for (int i = 0; i < n; i++)
        cout << arr[i] << " ";
}
  
// Function to print the array with
// maximum mean
void printMaxMean(int arr[], int n)
{
    int newArr[n];
  
    // Sort the original array
    sort(arr, arr + 2 * n);
  
    // Construct new array
    for (int i = 0; i < n; i++)
        newArr[i] = arr[i + n];
  
    // Print the resultant array
    printArray(newArr, n);
}
  
// Driver code
int main()
{
    int arr[] = { 4, 8, 3, 1, 3, 7, 0, 4 };
    int n = sizeof(arr) / sizeof(arr[0]);
    printMaxMean(arr, n / 2);
  
    return 0;
}

Java

// Java implementation of the approach
import java.util.Arrays;
  
class GfG{
  
    // Utility function to print the  
    // contents of an array 
    static void printArray(int arr[], int n) 
    { 
        for (int i = 0; i < n; i++) 
            System.out.print(arr[i] + " "); 
    } 
      
    // Function to print the array  
    // with maximum mean 
    static void printMaxMean(int arr[], int n) 
    { 
        int newArr[] = new int[n]; 
      
        // Sort the original array 
        Arrays.sort(arr, 0, 2 * n);
      
        // Construct new array 
        for (int i = 0; i < n; i++) 
            newArr[i] = arr[i + n]; 
      
        // Print the resultant array 
        printArray(newArr, n); 
    } 
  
    // Driver code
    public static void main(String []args)
    {
        int arr[] = { 4, 8, 3, 1, 3, 7, 0, 4 }; 
        int n = arr.length; 
        printMaxMean(arr, n / 2); 
    }
}
  
// This code is contributed by
// Rituraj Jain

Python3

# Python3 implementation of the approach 
  
# Utility function to print the contents 
# of an array 
def printArray(arr, n) :
    for i in range(n) : 
        print(arr[i], end = " ")
  
# Function to print the array with 
# maximum mean 
def printMaxMean(arr, n) :
    newArr = [0] * n 
  
    # Sort the original array 
    arr.sort()
  
    # Construct new array 
    for i in range(n) : 
        newArr[i] = arr[i + n]
  
    # Print the resultant array 
    printArray(newArr, n)
  
# Driver code 
if __name__ == "__main__" :
  
    arr = [ 4, 8, 3, 1, 3, 7, 0, 4 ] 
    n = len(arr) 
    printMaxMean(arr, n // 2) 
  
# This code is contributed by Ryuga

C#

// C# implementation of the approach
using System;
  
class GfG
{
  
    // Utility function to print the 
    // contents of an array 
    static void printArray(int[] arr, int n) 
    { 
        for (int i = 0; i < n; i++) 
            Console.Write(arr[i] + " "); 
    } 
      
    // Function to print the array 
    // with maximum mean 
    static void printMaxMean(int[] arr, int n) 
    { 
        int[] newArr = new int[n]; 
      
        // Sort the original array 
        Array.Sort(arr, 0, 2 * n);
      
        // Construct new array 
        for (int i = 0; i < n; i++) 
            newArr[i] = arr[i + n]; 
      
        // Print the resultant array 
        printArray(newArr, n); 
    } 
  
    // Driver code
    public static void Main()
    {
        int[] arr = { 4, 8, 3, 1, 3, 7, 0, 4 }; 
        int n = arr.Length; 
        printMaxMean(arr, n / 2); 
    }
}
  
// This code is contributed by Ita_c.

---

输出：

4 4 7 8