class Solution {

public:

    vector<int> powerfulIntegers(int x, int y, int bound) {

        unordered_set<int> tmp;

        for(int a=; a<bound; a*=x)//

        {

            for(int b=; a+b<=bound; b*=y)

            {

                tmp.insert(a+b);//

                if(y==) break;//

            }

            if(x==) break;

        }

        return vector<int>(tmp.begin(), tmp.end());

    }

};