If you like this, you'll also really like the Rosetta Code project. It also has tons of algorithms (and more languages), and lately is getting some traction. http://rosettacode.org/wiki/Rosetta_Code
And if you'd like to try your own hand at solving problems using some of these algorithms (a good way to get some hands-on practice in your favourite new language), Rosalind [1] offers a gentle learning curve.
There are hundreds of problems on the site, roughly graded by difficulty, easiest first. In the beginning you get to solve a few easy problems. As you solve each problem, more problems become available for you to try.
They are "a platform for learning bioinformatics through problem solving" so many of the problems are about strings, but there are also problems on graphs and other structures.
They also have a new section called "Algorithmic Heights", which is "A collection of exercises in introductory algorithms to accompany "Algorithms", the popular textbook by Dasgupta, Papadimitriou, and Vazirani." I have submitted this for discussion here: https://news.ycombinator.com/item?id=7456390
