Question

I’ve been looking into combinations lately, I’ve tried various 3rd party solutions, and tried to get my head around it myself. Without success I might add.

I need to generate a 13 length string with all possible combinations of say.. int 0-2, I.E

0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 1
0 0 0 0 0 0 0 0 0 0 0 0 2
0 0 0 0 0 0 0 0 0 0 0 1 0
... 
2 2 2 2 2 2 2 2 2 2 2 2 2

You probably get the drill, I’m aware I could just wrap this up in loops if I wanted a dirty solution. Any guidance or pointers are appreciated.

Answer 1

I can’t help thinking of this as just adding number in a N-based numeric system (in your example a 3-base system).

I would write one method (if not already there in the framework or a library) that would allow you to switch bases. I.E:

String transformNumberFrom10BaseToXBase(int number, int base)

then just write a for loop (sorry, pseudo-c-like-code 🙂 ):

for (int i = 0; i < base ^ 13; i++) {
    print transformNumberFrom10BaseToXBase(i, base)
}

Ok, hope that helps or give you an idea on how to solve it 🙂