NumberDivision.java

/**
 * https://codeforces.com/problemset/problem/1106/C #greedy #implementation #math #sorting the max
 * element must be divided in a group with another element that you have to make sure the the square
 * of group is minimum => sort the array and make two pointer: from left, right => make efficient
 * group
 */
import java.util.Arrays;
import java.util.Scanner;

public class NumberDivision {
  static long calMinSum() {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int[] arr = new int[n];
    for (int i = 0; i < n; i++) {
      int temp = sc.nextInt();
      arr[i] = temp;
    }
    Arrays.sort(arr);
    long result = 0;
    for (int i = 0, j = n - 1; i < j; i++, j--) {
      result += (long) (arr[i] + arr[j]) * (arr[i] + arr[j]);
    }

    return result;
  }

  public static void main(String[] args) {
    System.out.println(calMinSum());
  }
}