题解 | #称砝码#

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.Set;
import java.util.HashSet;

// 注意类名必须为 Main
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int len = in.nextInt();
            int[] weight = new int[len];
            int[] nums = new int[len];

            for (int i = 0; i < len; i++) {
                weight[i] = in.nextInt();
            }

            for (int i = 0; i < len; i++) {
                nums[i] = in.nextInt();
            }
            System.out.println(getWeightNum(weight, nums));
        }
        in.close();
    }
    private static int getWeightNum(int[] weight, int[] nums) {
        Set<Integer> set = new HashSet<>();
        set.add(0);
        //遍历砝码的种类
        for (int i = 0; i < nums.length; i++) {
            //System.out.println(i + "--------" + set.size());
            List<Integer> list = new ArrayList<>(set);
            //num[i]表示每种砝码的最大数量，可取值就是从0到num[i]
            for (int j = 0; j <= nums[i]; j++) {
                //System.out.println(j + "==" + list.size());
                //k是当前能测的所有重量+某个砝码从1个到最大值的各种质量放到set去重，就是当前能测得所有质量
                for (Integer k : list) {
                    set.add(k + weight[i] * j);
                    //System.out.println(j + "==" + i + "==" + weight[i] + "==" + j);
                }
            }
        }
        return set.size();
    }
}