Introduction to Algorithms, 2nd (or 3rd Edition)
by Cormen, Leiserson, Rivest, Stein
MIT Press, 2001 (or 2009).
Here's why I asked the bookstore to stock the 2nd edition: ISBN-13: 978-0070131514 ISBN-10: 0070131511
Interlude: xkcd code quality strips. enjoy!
Cracking the Coding Interview, 6th Edition
by Laakmann McDowell