将给定数组排序为降序最低升序形式

给定一个大小为N的数组arr[]和一个整数K ，任务是对数组进行排序，使得数组的前K 个元素按降序排列，数组的最后N – K 个元素按升序排列。

例子：

Input: arr[]= {7, 6, 8, 9, 0, 1, 2, 2, 1, 8, 9, 6, 7}, K = 6 
Output: 9 9 8 8 7 7 0 1 1 2 2 6 6 
Explanation: 
The first K (= 6) elements of the sorted array are {9, 9, 8, 8, 7, 7}, which are in descending order. 
The last N – K (= 6) elements of the sorted array are {0, 1, 1, 2, 2, 6, 6}, which are in ascending order. 
Therefore, the required output is 9 9 8 8 7 7 0 1 1 2 2 6 6

Input: arr[]= {65, 34, 54, 56, 75, 34, 54, 65, 56, 75, 15}, K = 5 
Output: 75 75 65 65 56 56 15 34 34 54 54

处理方法：按照以下步骤解决问题：

• 按降序对数组进行排序。
• 按升序对数组的最后(N – K) 个元素进行排序。
• 打印数组。

下面是上述方法的实现：

C++

// C++ program to implement
// the above approach
 
#include 
using namespace std;
 
// Function to sort first K array elements in
// descending and last N - K in ascending order
void sortArrayInDescAsc(int arr[], int N, int K)
{
    // Sort the array in descending order
    sort(arr, arr + N, greater());
 
    // Sort last (N - K) array
    // elements in ascending order
    sort(arr + K, arr + N);
 
    // Print array elements
    for (int i = 0; i < N; i++) {
        cout << arr[i] << " ";
    }
}
 
// Driver Code
int main()
{
    int arr[] = { 7, 6, 8, 9, 0, 1, 2,
                  2, 1, 8, 9, 6, 7 };
    int N = sizeof(arr) / sizeof(arr[0]);
    int K = 6;
    sortArrayInDescAsc(arr, N, K);
}

Java

// Java program to implement
// the above approach
import java.util.*;
 
class GFG{
 
// Function to sort first K array elements in
// descending and last N - K in ascending order
static void sortArrayInDescAsc(int arr[], int N,
                               int K)
{
     
    // Sort the array in descending order
    Arrays.sort(arr);
 
    for(int i = 0, j = N - 1; i < N / 2; i++)
    {
        int temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
        j--;
    }
 
    // Sort last (N - K) array
    // elements in ascending order
    Arrays.sort(arr, K, N);
 
    // Print array elements
    for(int i = 0; i < N; i++)
    {
        System.out.print(arr[i] + " ");
    }
}
 
// Driver Code
public static void main(String[] args)
{
    int arr[] = { 7, 6, 8, 9, 0, 1, 2,
                  2, 1, 8, 9, 6, 7 };
    int N = arr.length;
    int K = 6;
     
    sortArrayInDescAsc(arr, N, K);
}
}
 
// This code is contributed by Amit Katiyar

Python3

# Python3 program to implement
# the above approach
 
# Function to sort first K array
# elements in descending and last
# N - K in ascending order
def sortArrayInDescAsc(arr, N, K):
     
    # Sort the array in descending order
    arr = sorted(arr)
    arr = arr[::-1]
 
    # Sort last (N - K) array
    # elements in ascending order
    for i in arr[:K]:
        print(i, end = " ")
    for i in reversed(arr[K:]):
        print(i, end = " ")
 
# Driver Code
if __name__ == '__main__':
     
    arr = [ 7, 6, 8, 9, 0, 1,
            2, 2, 1, 8, 9, 6, 7 ]
    N = len(arr)
    K = 6
     
    sortArrayInDescAsc(arr, N, K)
 
# This code is contributed by mohit kumar 29

C#

// C# program to implement
// the above approach 
using System;
 
class GFG{
      
// Function to sort first K array elements in
// descending and last N - K in ascending order
static void sortArrayInDescAsc(int[] arr, int N,
                               int K)
{
     
    // Sort the array in descending order
    Array.Sort(arr);
    Array.Reverse(arr);
  
    // Sort last (N - K) array
    // elements in ascending order
    int temp = 0;
     
    for(int i = K; i < N; i++)
    {
        for(int j = i + 1; j < N; j++)
        {    
            if (arr[i] > arr[j])
            {
                temp = arr[i];   
                arr[i] = arr[j];   
                arr[j] = temp;   
            }    
        }    
    }
  
    // Print array elements
    for(int i = 0; i < N; i++)
    {
        Console.Write(arr[i] + " ");
    }
}
  
// Driver code
public static void Main()
{
    int[] arr = { 7, 6, 8, 9, 0, 1, 2,
                  2, 1, 8, 9, 6, 7 };
    int N = arr.Length;
    int K = 6;
     
    sortArrayInDescAsc(arr, N, K);
}
}
 
// This code is contributed by sanjoy_62

Javascript

  
// Javascript program to implement
// the above approach
 
// Function to sort first K array elements in
// descending and last N - K in ascending order
function sortArrayInDescAsc(arr, N, K)
{
    // Sort the array in descending order
    arr.sort((b,a)=> a-b)
 
    var temp = 0;
     
    for(var i = K; i < N; i++)
    {
        for(var j = i + 1; j < N; j++)
        {    
            if (arr[i] > arr[j])
            {
                temp = arr[i];   
                arr[i] = arr[j];   
                arr[j] = temp;   
            }    
        }    
    }
 
    // Print array elements
    arr.forEach(element => {
        document.write(element+" ");
    });
}
 
// Driver Code
var arr = [7, 6, 8, 9, 0, 1, 2,
              2, 1, 8, 9, 6, 7 ];
var N = arr.length;
var K = 6;
sortArrayInDescAsc(arr, N, K);
 
//This code is contributed by rrrtnx.

输出：

9 9 8 8 7 7 0 1 1 2 2 6 6

时间复杂度： O(N * log(N))
辅助空间： O(1)

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