满帮10.11笔试，第一题为什么为0

代码如下，感觉应该是对的，但是一直是0分，非常疑惑。。。

import java.util.Scanner;
/**
 * Create by zekdot on 2022/9/19.
 */
public class Main {
    public int solution(int n, int[] a, int[] b) {
        // 求出最大苹果数量，最大糖果数量
        int maxA = 0, maxB = 0;
        for (int i = 0; i < n; i ++) {
            maxA = Math.max(maxA, a[i]);
            maxB = Math.max(maxB, b[i]);
        }
        int res = 0;
        for (int i = 0; i < n; i ++) {
            // 以苹果为基准进行放置
            if (a[i] < maxA) {
                if (b[i] < maxB) {
                    // 糖果和苹果都不够
                    res += Math.max(maxA - a[i], maxB - b[i]);
                } else {
                    // 只需要关心苹果
                    res += maxA - a[i];
                }
            } else {
                // 只需要关注糖果
                res += maxB - b[i];
            }
        }
        return res;
    }
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        Main main = new Main();
        int T = scanner.nextInt();
        while (T -- > 0) {
            int n = scanner.nextInt();
            int[] a = new int[n], b = new int[n];
            for (int i = 0; i < n; i ++) {
               a[i] = scanner.nextInt();
               b[i] = scanner.nextInt();
            }
           System.out.println(main.solution(n, a, b));
        }
        scanner.close();
    }
}