题解 | 称砝码

#include<bits/stdc++.h>
using namespace std;
#define IOS ios_base::sync_with_stdio(false);cin.tie(nullptr)
#define INF 0x7fffffff
#define inf 0x3f3f3f3f
#define PII pair<int,int>
#define endl '\n'
#define int long long
#define double long double
#define mod 998244353
int read() {char act = 0;int f = 1, x= 0;while (act = getchar(), act < '0' && act != '-');if (act == '-') f = -1, act = getchar();x = act - '0';while (act = getchar(), act >= '0') x = x * 10 + act - '0';return x * f;}
void solve(){
    int n;
    cin>>n;
    vector<int>w(n),cnt(n);
    for(int i=0;i<n;i++){
        cin>>w[i];
    }
    for(int i=0;i<n;i++){
        cin>>cnt[i];
    }
    unordered_set<int>st;//存答案
    st.insert(0);
    for(int i=0;i<n;i++){
        for(int j=1;j<=cnt[i];j++){
            unordered_set<int>temp(st);
            for(auto k:temp){
                st.insert(k+w[i]);
            }
        }
    }
    cout<<st.size()<<endl;
}
signed main()
{
    IOS; 
    int t=1;
    //cin>>t;
    while(t--){
        solve();
    }

    return 0;
}