题解 | #称砝码#

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while (in.hasNext()) { 
            int N = Integer.parseInt(in.nextLine());
            String[] weight = in.nextLine().split(" ");
            String[] ma = in.nextLine().split(" ");
            Map<Integer, Integer> map = new HashMap<>();
            for (int i = 0; i < N; i++) {
                map.put(Integer.parseInt(weight[i]), Integer.parseInt(ma[i]));
            }
            Map<Integer, Integer> res = new HashMap<>();
            res.put(0, 1);
            for (int b : map.keySet()) {
                for (int i = 0; i < map.get(b); i++) {
                    Set<Integer> set = res.keySet();
                    // 存入新的集合中
                    Set<Integer> newSet = new HashSet<>(set);//将key保存到新的set，否则put之后会越界
                    for (int c : newSet) {
                        res.put(c + b, 1);
                    }
                }
            }
            System.out.println(res.size());
        }
    }
}