Head First Algorithms and Data Structures

Appendix A. Leftovers The Top Ten Topics (We Didn’t Cover)

A Note for Early Release Readers

With Early Release ebooks, you get books in their earliest form—the author’s raw and unedited content as they write—so you can take advantage of these technologies long before the official release of these titles.

This will be the appendix of the final book.

If you’d like to be actively involved in reviewing and commenting on this draft, please reach out to the editor at [e-mail].

We’ve covered a lot of ground, and you’re almost finished with this book. We’ll miss you, but before we let you go, we wouldn’t feel right about sending you out into the world without a little more preparation. We can’t possibly fit everything you’ll need to know into this relatively small chapter. Actually, we did originally include everything you need to know about algorithms and data structures (not already covered by the other chapters), by reducing the type point size to .00004. It all fit, but nobody could read it. So we threw most of it away, and kept the best bits for this Top Ten Appendix A. This really is the end of the book. Except for the index, of course (a must-read!).

#1 Tries (Prefix Trees)

Ever wonder how your phone knows you’re typing “hello” after just “hel”?

It’s not magic, and it’s not checking every word in the dictionary. It’s a trie: a tree where each path from root to leaf ...