Ok, every recruiter from a tech company says the same thing before you're interview:
Study up on algorithms, as they will ask you about that during the
interview.
Since you've basically quoted that sentence verbatum, I'm going to make the not-so-outlandish-guess that you're interviewing for a major tech company (whether it is Google, Microsoft, Apple, Amazon, or what not--they all do the same thing to their candidates).
You need books that focus on the algorithms they will quiz you on during the interview, as this will give you a better idea of what to expect. My recommendations:

http://www.amazon.com/Programming-Interviews-Exposed-Secrets-Programmer/dp/047012167X/ref=sr_1_2?s=books&ie=UTF8&qid=1348063912&sr=1-2&keywords=coding+interview
And

http://www.amazon.com/Cracking-Coding-Interview-Programming-Questions/dp/098478280X
I highly recommend that you read these books, especially the first one (wink, wink, nudge, nudge, cough--Imightbetalkingfromexperience--cough ).
In all seriousness though, a programming interview at a major tech company is nothing like interviews everywhere else. You need to be prepared for it because you're going up against people who have been preparing for months.
Read the books, practice writing code on paper, and knock it out of the park :)