This Competitive Programming book, 4th edition CP4 is a must have for every competitive programmer. Mastering the contents of this book is a necessary but admittedly not sufficient condition if one wishes to take a leap forward from being just another ordinary coder to being among one of the world's finest competitive programmers. Typical readers of Book 1 only of CP4 would include 1. Secondary or High School Students who are competing in the annual International Olympiad in Informatics IOI including the National or Provincial Olympiads as Book 1 covers most of the current IOI Syllabus, 2. Casual University students who are using this book as supplementary material for typical Data Structures and Algorithms courses, 3. Anyone who wants to prepare for typical fundamental data structurealgorithm part of a job interview at top IT companies. Typical readers of both Book 1 Book 2 of CP4 would include 1. University students who are competing in the annual International Collegiate Programmin