Algorithms

The Road to Algorithms Enlightenment

https://icpc.baylor.edu/

http://acm.timus.ru/

https://uva.onlinejudge.org/

https://www.topcoder.com/

https://www.codechef.com/

https://leetcode.com

https://www.coursera.org/courses?query=algorithms

http://www.ntu.edu.sg/home/xhbei/MAS714.html

https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-006-introduction-to-algorithms-spring-2008/

Participation

https://leetcode.com/problemset/all/

https://www.hackerrank.com/domains/java/

https://www.w3resource.com/java-exercises/

Algorithmic Complexity

https://www.cs.cmu.edu/~adamchik/15-121/lectures/Algorithmic%20Complexity/complexity.html

https://computationalcomplexity.org/conferences.php

http://ac.informatik.uni-freiburg.de