CSES
CSES Problem Set

The CSES Problem Set contains a collection of competitive programming practice problems. You can access the problems here.
Datatähti-valmennus

Kokoelma harjoitustehtäviä, joiden avulla voit harjoitella Datatähteä ja muita kilpailuja varten. Pääset tehtäviin tästä.
Competitive programming books

Do you want to learn competitive programming? You can find a collection of recent competitive programming books here.
BOI Contest Collection

This collection contains all Baltic Olympiad in Informatics contests from 2005 to 2019. You can access the contests here.

CEOI Contest Collection

This collection contains all Central European Olympiad in Informatics contests from 2005 to 2019. You can access the contests here.