Problem Sets

Problem sets turn what you read into skill. Beginners do well with sites that check small exercises and give feedback, such as Exercism, Edabit and CodingBat. Advent of Code publishes a set of puzzles each December that work in any language, and Project Euler mixes programming with mathematics.

For interview preparation, curated lists such as NeetCode 150, Grind 75 and LeetCode's Top Interview 150 keep practice focused on common patterns. Competitive programmers can work through the CSES Problem Set, Codeforces or Kattis, and Rosalind applies programming to bioinformatics. Solving a few problems regularly works better than occasional long sessions.