题解 | #称砝码#

#include<iostream>
#include<vector>
#include<unordered_set>
using namespace std;

int main(){
    int n ;
    cin >> n;
    vector<int> weight(n);
    vector<int> nums(n);
    for(int i = 0; i < n ; i++){
        cin >> weight[i];
    }
    for(int j = 0 ; j < n ; j++)
        cin >> nums[j];

    unordered_set<int> set;
    set.insert(0);
    for(int i = 0; i < n; i++){
        // 遍历重量数组
        int cur_weight = weight[i];
        int cur_num = nums[i];
        while(cur_num--){
            unordered_set<int> cur_set(set);
            for(auto it = cur_set.begin(); it!= cur_set.end(); it++)
                set.insert( *it + cur_weight);
        }
    }
    cout << set.size() << endl;

}