从给定数组中选择 K 个元素求表达式的最小值
原文:https://www . geeksforgeeks . org/通过从给定数组中选择 k 个元素来查找表达式的最小值/
给定一个大小为 N 的整数数组 arr ，任务是通过从给定数组 arr 中精确选择 K(≤ N) 整数来找到表达式的最小可能值。假设所选元素存储在数组 B (B 1 、B 2 、B 3 …..B k ) 那么表达式的值: T21】
示例:
输入: arr[] = {2，0，9，5}，k = 2 输出: 8 假设选择的元素是{2，0}，那么 x = 8，这是最小可能值
输入: arr[] = {4，21，5，3，8}，k = 3 T3】输出: 200
进场: 以上表述可简化为:
所以，我们需要做的就是从数组中选择 k 个最小的元素，求解表达式。
下面是上述方法的实现:
C++
// CPP program to find the minimum possible of the expression
// by choosing exactly K(? N) integers form given array arr
#include <bits/stdc++.h>
using namespace std;
// Function to find the minimum possible of the expression
// by choosing exactly K(? N) integers form given array arr
int minimumValue(int arr[], int n, int k)
{
// Sorting the array for least k element selection
sort(arr, arr + n);
int answer = 0;
// Select first k elements from sorted array
for (int i = 0; i < k; i++)
answer += arr[i] * arr[i];
// Return value of solved expression
return answer * (2 * k - 2);
}
// Driver code
int main()
{
int arr[] = { 4, 21, 5, 3, 8 }, k = 3;
int n = sizeof(arr) / sizeof(arr[0]);
// Function call
cout << minimumValue(arr, n, k);
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// JAVA program to find the minimum possible of the expression
// by choosing exactly K(? N) integers form given array arr
import java.util.*;
class GFG{
// Function to find the minimum possible of the expression
// by choosing exactly K(? N) integers form given array arr
static int minimumValue(int arr[], int n, int k)
{
// Sorting the array for least k element selection
Arrays.sort(arr);
int answer = 0;
// Select first k elements from sorted array
for (int i = 0; i < k; i++)
answer += arr[i] * arr[i];
// Return value of solved expression
return answer * (2 * k - 2);
}
// Driver code
public static void main(String[] args)
{
int arr[] = { 4, 21, 5, 3, 8 }, k = 3;
int n = arr.length;
// Function call
System.out.print(minimumValue(arr, n, k));
}
}
// This code is contributed by Rajput-Ji
Python 3
# Python program to find the minimum
# possible of the expression by choosing
# exactly K(? N) integers form given array arr
# Function to find the minimum
# possible of the expression by
# choosing exactly K(? N) integers
# form given array arr
def minimumValue(arr, n, k):
# Sorting the array for least k element selection
arr.sort();
answer = 0;
# Select first k elements from sorted array
for i in range(k):
answer += arr[i] * arr[i];
# Return value of solved expression
return answer * (2 * k - 2);
# Driver code
if __name__ == '__main__':
arr = [ 4, 21, 5, 3, 8 ];
k = 3;
n = len(arr);
# Function call
print(minimumValue(arr, n, k));
# This code is contributed by Rajput-Ji
C
// C# program to find the minimum possible of the expression
// by choosing exactly K(? N) integers form given array arr
using System;
class GFG{
// Function to find the minimum possible of the expression
// by choosing exactly K(? N) integers form given array arr
static int minimumValue(int []arr, int n, int k)
{
// Sorting the array for least k element selection
Array.Sort(arr);
int answer = 0;
// Select first k elements from sorted array
for (int i = 0; i < k; i++)
answer += arr[i] * arr[i];
// Return value of solved expression
return answer * (2 * k - 2);
}
// Driver code
public static void Main(String[] args)
{
int []arr = { 4, 21, 5, 3, 8 };
int k = 3;
int n = arr.Length;
// Function call
Console.Write(minimumValue(arr, n, k));
}
}
// This code is contributed by 29AjayKumar
java 描述语言
<script>
// JavaScript program to find the minimum possible of the expression
// by choosing exactly K(? N) integers form given array arr
// Function to find the minimum possible of the expression
// by choosing exactly K(? N) integers form given array arr
function minimumValue(arr, n, k)
{
// Sorting the array for least k element selection
arr.sort((a, b) => a - b);
let answer = 0;
// Select first k elements from sorted array
for (let i = 0; i < k; i++)
answer += arr[i] * arr[i];
// Return value of solved expression
return answer * (2 * k - 2);
}
// Driver code
let arr = [ 4, 21, 5, 3, 8 ], k = 3;
let n = arr.length;
// Function call
document.write(minimumValue(arr, n, k));
// This code is contributed by Surbhi Tyagi.
</script>
Output:
200
时间复杂度:O(n * log n)
辅助空间:0(1)
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