simple solution of sumof

sumof.cpp

#include <iostream>
#include <vector>

bool sum_of(std::vector<int> const & list, int const target, int const maxdep)
{
    if (maxdep < 0 or target < 0)
        return false;
    if (target == 0)
        return true;

    for (int const & value : list)
        if (sum_of(list, target - value, maxdep - 1))
        {
            std::cout << value << " ";
            return true;
        }
    return false;
}

int main()
{
    std::vector<int> sums;
    for (int i = 2; i < 100; i++)
        sums.push_back(i * i);

    auto print_sum_of = [&sums](int target, int maxdep) {
        std::cout << target << " = ";
        sum_of(sums, target, maxdep);
        std::cout << "\n";
    };

    for (int i = 2; i <= 5; i++)
    {
        std::cout << "by " << i << "\n";
        print_sum_of(1035, i);
        print_sum_of(1054, i);
        print_sum_of(1078, i);
        print_sum_of(2146, i);
        print_sum_of(2356, i);
    }
}