最小乘积

/**

* 给两组数，各n个。

* 请调整每组数的排列顺序，使得两组数据相同下标元素对应相乘，然后相加的和最小。

*/

import java.util.*;

import java.io.*;

public class 最小乘积 {

public static void JianArray(Integer[] b1) {

Arrays.sort(b1);

int i = 0, n = b1.length - 1;

while (n > 2 * i) {

Integer t = b1[i];

b1[i] = b1[n - i];

b1[n - i] = t;

i++;

}

}

public static void main(String[] args) {

Scanner in = new Scanner(new BufferedInputStream(System.in));

int n = in.nextInt();

for (int i = 0; i < n; i++) {

int num = in.nextInt();

Integer[] a = new Integer[num];

Integer[] b = new Integer[num];

for (int j = 0; j < num; j++) {

a[j] = in.nextInt();

}

for (int j = 0; j < num; j++) {

b[j] = in.nextInt();

}

Arrays.sort(a);

JianArray(b);

int sum = 0;

for (int j = 0; j < num; j++) {

sum += a[j] * b[j];

}

System.out.println(sum);

}

}

}