Qualitative literature or sites on algorithms and solving Olympiad problems?

Question

Algorithms

Please advise any books, with the exception of Kormen and Knuth, or sites related to the theory of algorithms, the solution of some non-trivial problems and Olympiad problems. It is desirable that it was as clear as possible, graphically illustrated and interesting to read (although this is too serious a request)

Answer 1

I liked algolist.manual.ru/ from Ilya Kantor

Answer 2

There is also e-maxx.ru/algo/
And here are the visualizers: rain.ifmo.ru/cat/view.php/vis

Answer 3

Just recently, a resource was advised on Habré: acm.timus.ru/

Answer 4

More for practice in problem solving:
acmp.ru
www.topcoder.com