Free (draft of) book on algorithms (see Official URL for link).
The book is oriented toward preparing for competitive programming competitions. It covers many fundamental algorithm types and commonly studied algorithms. The exercises are links to Kattis free online judging system. The book has examples in C++ as well as a short introduction.
Currently reading: I came across this book while looking for a list of Kattis problems what would exhibit classical problems and algorithms like Kattis’ Traveling SalesPerson problem (problem ID: tsp). This book is even better with the background and the corresponding problems in one place.