Probably this has been shown by somebody else before but just to make my first post: I found the suggested difficulty level for tripleX too easy and modified it as follows:
const int CodeA = Difficulty + rand() % (Difficulty + 2);
const int CodeB = Difficulty + rand() % (Difficulty + 1);
const int CodeC = Difficulty + rand() % (Difficulty);
As such you won’t start with 1 1 1 all the time.
Cheers