public static IEnumerable <int> GenSampleIterator(bool sol = false)
{
List <int> lst = new List <int> {
1, 2, 5
};
var sample = sol
? IteratorExp <int> .GenSample_solution(lst, -2)
: IteratorExp <int> .GenSample_problem(lst, -2);
return(sample);
}