将数组拆分为 K 个非空子集，以使它们的最大值和最小值之和最大化

给定两个由N和K 个整数组成的数组arr[]和S[] ，任务是在将数组分成K个子集后，找到每个子集的最小值和最大值的最大和，使得每个子集的大小等于 1数组S[]中的元素。

例子：

Input: arr[] = {1, 13, 7, 17}, S[] = {1, 3}
Output: 48
Explanation: Consider splitting the array as {17}, {1, 7, 13}, such that the size of subsets are 1 and 3 respectively, which is present in the array S[].
The sum of the maximum and minimum of each subset is (17 + 17 + 1 + 13) = 48.

Input: arr[ ] = {5, 1, -30, 0, 11, 20, 19}, S[] = {4, 1, 2} 
Output: 45

方法：给定的问题可以使用贪心方法来解决，其思想是在每个组中插入前K 个最大元素，然后首先用较大的元素开始填充较小的组。请按照以下步骤解决问题：

• 初始化一个变量，比如ans为0 ，以存储所有子集的最大值和最小值的总和。
• 按降序对数组arr[]进行排序。
• 按升序对数组S[]进行排序。
• 找到数组前K 个元素的总和并将其存储在变量ans 中，并将S[]的所有元素减1 。
• 初始化一个变量，比如counter为K – 1 ，以存储每个子集的最小元素的索引。
• 遍历数组S[]并通过S[i]增加 counter 并将arr[counter]的值添加到ans 。
• 完成上述步骤后，打印ans的值作为结果。

下面是上述方法的实现：

C++

// C++ program for the above approach
 
#include 
using namespace std;
 
// Function find maximum sum of
// minimum and maximum of K subsets
int maximumSum(int arr[], int S[],
               int N, int K)
{
    // Stores the result
    int ans = 0;
 
    // Sort the array arr[] in
    // decreasing order
    sort(arr, arr + N, greater());
 
    // Traverse the range [0, K]
    for (int i = 0; i < K; i++)
        ans += arr[i];
 
    // Sort the array S[] in
    // ascending order
    sort(S, S + K);
 
    // Traverse the array S[]
    for (int i = 0; i < K; i++) {
 
        // If S{i] is 1
        if (S[i] == 1)
            ans += arr[i];
 
        S[i]--;
    }
 
    // Stores the index of the minimum
    // element of the i-th subset
    int counter = K - 1;
 
    // Traverse the array S[]
    for (int i = 0; i < K; i++) {
 
        // Update the counter
        counter = counter + S[i];
 
        if (S[i] != 0)
            ans += arr[counter];
    }
 
    // Return the resultant sum
    return ans;
}
 
// Driver Code
int main()
{
    int arr[] = { 1, 13, 7, 17 };
    int S[] = { 1, 3 };
    int N = sizeof(arr) / sizeof(arr[0]);
    int K = sizeof(S) / sizeof(S[0]);
    cout << maximumSum(arr, S, N, K);
 
    return 0;
}

Java

// Java program for the above approach
import java.io.*;
import java.lang.*;
import java.util.*;
 
class GFG{
 
// Function find maximum sum of
// minimum and maximum of K subsets
static int maximumSum(int arr[], int S[],
                      int N, int K)
{
     
    // Stores the result
    int ans = 0;
 
    // Sort the array arr[] in
    // decreasing order
    Arrays.sort(arr);
    for(int i = 0; i < N / 2; i++)
    {
        int temp = arr[i];
        arr[i] = arr[N - 1 - i];
        arr[N - 1 - i] = temp;
    }
 
    // Traverse the range [0, K]
    for(int i = 0; i < K; i++)
        ans += arr[i];
 
    // Sort the array S[] in
    // ascending order
    Arrays.sort(S);
 
    // Traverse the array S[]
    for(int i = 0; i < K; i++)
    {
         
        // If S{i] is 1
        if (S[i] == 1)
            ans += arr[i];
 
        S[i]--;
    }
 
    // Stores the index of the minimum
    // element of the i-th subset
    int counter = K - 1;
 
    // Traverse the array S[]
    for(int i = 0; i < K; i++)
    {
 
        // Update the counter
        counter = counter + S[i];
 
        if (S[i] != 0)
            ans += arr[counter];
    }
 
    // Return the resultant sum
    return ans;
}
 
// Driver Code
public static void main(String[] args)
{
    int arr[] = { 1, 13, 7, 17 };
    int S[] = { 1, 3 };
    int N = arr.length;
    int K = S.length;
     
    System.out.println(maximumSum(arr, S, N, K));
}
}
 
// This code is contributed by Kingash

Python3

# Python3 program for the above approach
 
# Function find maximum sum of
# minimum and maximum of K subsets
def maximumSum(arr, S, N, K):
     
    # Stores the result
    ans = 0
 
    # Sort the array arr[] in
    # decreasing order
    arr = sorted(arr)[::-1]
 
    # Traverse the range [0, K]
    for i in range(K):
        ans += arr[i]
 
    # Sort the array S[] in
    # ascending order
    S = sorted(S)
 
    # Traverse the array S[]
    for i in range(K):
         
        # If S{i] is 1
        if (S[i] == 1):
            ans += arr[i]
 
        S[i] -= 1
 
    # Stores the index of the minimum
    # element of the i-th subset
    counter = K - 1
 
    # Traverse the array S[]
    for i in range(K):
         
        # Update the counter
        counter = counter + S[i]
 
        if (S[i] != 0):
            ans += arr[counter]
 
    # Return the resultant sum
    return ans
 
# Driver Code
if __name__ == '__main__':
     
    arr = [ 1, 13, 7, 17 ]
    S = [ 1, 3 ]
    N = len(arr)
    K = len(S)
     
    print (maximumSum(arr, S, N, K))
 
# This code is contributed by mohit kumar 29

C#

// C# program for the above approach
using System;
class GFG {
 
    // Function find maximum sum of
    // minimum and maximum of K subsets
    static int maximumSum(int[] arr, int[] S, int N, int K)
    {
 
        // Stores the result
        int ans = 0;
 
        // Sort the array arr[] in
        // decreasing order
        Array.Sort(arr);
        for (int i = 0; i < N / 2; i++) {
            int temp = arr[i];
            arr[i] = arr[N - 1 - i];
            arr[N - 1 - i] = temp;
        }
 
        // Traverse the range [0, K]
        for (int i = 0; i < K; i++)
            ans += arr[i];
 
        // Sort the array S[] in
        // ascending order
        Array.Sort(S);
 
        // Traverse the array S[]
        for (int i = 0; i < K; i++) {
 
            // If S{i] is 1
            if (S[i] == 1)
                ans += arr[i];
 
            S[i]--;
        }
 
        // Stores the index of the minimum
        // element of the i-th subset
        int counter = K - 1;
 
        // Traverse the array S[]
        for (int i = 0; i < K; i++) {
 
            // Update the counter
            counter = counter + S[i];
 
            if (S[i] != 0)
                ans += arr[counter];
        }
 
        // Return the resultant sum
        return ans;
    }
 
    // Driver Code
    public static void Main(string[] args)
    {
        int[] arr = { 1, 13, 7, 17 };
        int[] S = { 1, 3 };
        int N = arr.Length;
        int K = S.Length;
 
        Console.WriteLine(maximumSum(arr, S, N, K));
    }
}
 
// This code is contributed by ukasp.

Javascript

 
// JavaScript program for the above approach
 
// Function find maximum sum of
// minimum and maximum of K subsets
function maximumSum(arr, S, N, K)
{
    // Stores the result
    var ans = 0;
    var i;
    // Sort the array arr[] in
    // decreasing order
    arr.sort((a, b) => b - a);
     
     
    // Traverse the range [0, K]
    for (i = 0; i < K; i++)
        ans += arr[i];
 
    // Sort the array S[] in
    // ascending order
    S.sort();
    // S.reverse();
    // Traverse the array S[]
    for (i = 0; i < K; i++) {
 
        // If S{i] is 1
        if (S[i] == 1)
            ans += arr[i];
 
        S[i] -= 1;
    }
 
    // Stores the index of the minimum
    // element of the i-th subset
    var counter = K - 1;
 
    // Traverse the array S[]
    for (i = 0; i < K; i++) {
 
        // Update the counter
        counter = counter + S[i];
 
        if (S[i] != 0)
            ans += arr[counter];
    }
 
    // Return the resultant sum
    return ans;
}
 
// Driver Code
    var arr = [1, 13, 7, 17];
    var S = [1, 3];
    var N = arr.length;
    var K = S.length;
    document.write(maximumSum(arr, S, N, K));
 

输出：

48

时间复杂度： O(N)
辅助空间： O(1)

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