How to improve a brute-forcing algorithm using groups?

Question

I got an excercise in which I have to guess a password using a brute-forcing algorithm. The charset is 'a-z' and the length varies between 3 and 6.

With 2GB of RAM I'm getting memory allocation errors after a couple of hours on the examples with 5 and 6 characters. I asked my teacher and he told me to do the bruteforcing using groups of 3, but I don't know how to approach this.

Answer 1

I don't know what your instructor meant, you should ask him or her for a clarification.

However, why do you need a lot of memory? You don't need to keep all the possible passwords in memory, just the one you're trying now.