Young Adult Literature, Coming-Of-Age, Adventure
This one's kind of a no-brainer: Colin, Hassan, and Lindsey are all teenagers who are looking for their way in life. Colin may be dealing with all the ups and downs of being a child prodigy, but he's still dealing with all the normal teenage preoccupations like dating, getting dumped, and figuring out what he wants to do with his life. Teenagers dealing with teenage problems? Sounds like this book was written for teenagers, which means it's definitely young adult lit.
Even though Colin has just graduated high school and is a brainiac, he's more than a little stunted in his social and romantic growth. He only has one friend because he doesn't know how to interact with people. Plus, he's been dumped again and again by Katherines. But over the course of the book, he really starts to experience many of normal teenage things involved in the transition from childhood into adulthood—he becomes more independent, gets a job, makes a new friend, and figures out who he really is (underneath the whole child prodigy thing)… all of which means this is a coming-of-age tale.
There isn't a whole lot of adventure, but considering the key role Colin and Hassan's road trip plays in the rest of the book—particularly Colin's personal growth—and the occasional sneaking around and spying the group endeavors, it's fair to say this book has a crush on the adventure genre, if not a full-blown relationship.