For algorithms training[1], the USA Computer Olympiad training program is also excellent: http://train.usaco.org/usacogate http://train.usaco.org/usacogate [1]

For algorithms training[1], the USA Computer Olympiad training program is also excellent: http://train.usaco.org/usacogate http://train.usaco.org/usacogate [1] basically from scratch; it's suitable for smart highschoolers with some programming experience. That website has been responsible for more than a few IOI medals.