One possible mistake in C18 problem 18.1-3

[tsatolol]

I think that the answer is a bit short.

Text says "Every node may contain at most 2t - 1 keys". If t = 2 then the B-tree root note contain at most 3 keys. As a result, the following is also the answer.

2 4 1 3 5

Don't think so?

[samolisov]

I agree with your answer and have proposed a PR #295. If we have a look at fig 18.1, we have a chance to see something a bit similar:

      D, H
B,C F,G  J,K,L

It can be a child node between keys in the parent.