3774-AbsoluteDifferenceBetweenMaximumAndMinimumKElements.go

package main

// 3774. Absolute Difference Between Maximum and Minimum K Elements
// You are given an integer array nums and an integer k.

// Find the absolute difference between:
//     1. the sum of the k largest elements in the array; and
//     2. the sum of the k smallest elements in the array.

// Return an integer denoting this difference.

// Example 1:
// Input: nums = [5,2,2,4], k = 2
// Output: 5
// Explanation:
// The k = 2 largest elements are 4 and 5. Their sum is 4 + 5 = 9.
// The k = 2 smallest elements are 2 and 2. Their sum is 2 + 2 = 4.
// The absolute difference is abs(9 - 4) = 5.

// Example 2:
// Input: nums = [100], k = 1
// Output: 0
// Explanation:
// The largest element is 100.
// The smallest element is 100.
// The absolute difference is abs(100 - 100) = 0.
 
// Constraints:
//     1 <= n == nums.length <= 100
//     1 <= nums[i] <= 100
//     1 <= k <= n

import "fmt"
import "sort"

func absDifference(nums []int, k int) int {
    sort.Ints(nums)
    mn, mx, n := 0, 0, len(nums)
    for i := 0; i < k; i++ {
        mn += nums[i]
        mx += nums[n-1-i]
    }
    abs := func(x int) int { if x < 0 { return -x; }; return x; }
    return abs(mx - mn)
}

func main() {
    // Example 1:
    // Input: nums = [5,2,2,4], k = 2
    // Output: 5
    // Explanation:
    // The k = 2 largest elements are 4 and 5. Their sum is 4 + 5 = 9.
    // The k = 2 smallest elements are 2 and 2. Their sum is 2 + 2 = 4.
    // The absolute difference is abs(9 - 4) = 5.
    fmt.Println(absDifference([]int{5,2,2,4}, 2)) // 5
    // Example 2:
    // Input: nums = [100], k = 1
    // Output: 0
    // Explanation:
    // The largest element is 100.
    // The smallest element is 100.
    // The absolute difference is abs(100 - 100) = 0.
    fmt.Println(absDifference([]int{100}, 1)) // 0

    fmt.Println(absDifference([]int{1,2,3,4,5,6,7,8,9}, 2)) // 14
    fmt.Println(absDifference([]int{9,8,7,6,5,4,3,2,1}, 2)) // 14
}