The problems in this book are fantastic training for interviews at the big tech companies. Google, Twitter and Facebook and the likes will grill you on algorithms and data structures and the run times of your code at least once for phone screen and 4-5 times in a single day at an onsite. You need to be fast and thorough. This book provides you with the practice and solutions that do a really good job of explaining the answers to questions similar to though encountered in a real interview process. I suggest having another book to teach you the fundamentals and theories and then hone your skills by doing the problems in this book.