题解 | 称砝码

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

// 注意类名必须为 Main, 不要有任何 package xxx 信息
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 a = in.nextInt();
            // int b = in.nextInt();
            // System.out.println(a + b);
            int n = in.nextInt();
            int[] ws = new int[n];
            int[] qs = new int[n];

            for (int i=0;i<n;i++){
                ws[i] = in.nextInt();
            }
            for (int i=0;i<n;i++){
                qs[i] = in.nextInt();
            }

            HashSet<Integer> set = new HashSet<>();
            set.add(0);
            for (int i=0;i<n;i++) {
                ArrayList<Integer> list = new ArrayList<>(set);
                for (int j=1;j<=qs[i];j++) {
                    for (int wq : list) {
                        set.add(wq + ws[i]*j);
                    }
                }
            }

            System.out.println(set.size());
        }
    }
}