ALGO-53 最小乘积(基本型)

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int t = sc.nextInt();

        while (0 != t--) {
            List<Integer> l1 = new ArrayList<Integer>();
            List<Integer> l2 = new ArrayList<Integer>();
            int n = sc.nextInt();
            for (int i = 0; i < n; i++) {
                l1.add(sc.nextInt());
            }
            for (int i = 0; i < n; i++) {
                l2.add(sc.nextInt());
            }
            Collections.sort(l1);
            Collections.sort(l2);
            int sum = 0;
            for (int i = 0; i < n; i++) {
                sum += l1.get(i) * l2.get(n - i - 1);
            }
            System.out.println(sum);

        }
        sc.close();
    }
}