题解 | 称砝码

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

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

    set<int> weights;
    weights.insert(0);

    for(int i = 0; i < n; ++i) {
        vector<int> currentWeights(weights.begin(), weights.end());
        for(int j = 1; j <= num[i]; ++j) {
            for(int k = 0; k < currentWeights.size(); ++k) {
                int newWeight = currentWeights[k] + j * weight[i];
                weights.insert(newWeight);
            }
        }
    }
    cout << weights.size() << endl;
    return 0;
}