Re: Permutation and Combination
This is a really fantastic article! I'd really appreciate some more help. Can you please explain how to find out the rank of a string when repetition of characters is allowed?
For instance, if I have the letters R, D, S, B and repetition of the letters is allowed, then the number of 4-letter strings = 4X4X4X4 = 256. So how do I find out what is the 110th string?