Programming Challenges and Learning Resources

A catalog of programming sites. Not exhaustive. No particular order.

• ProjectEuler
• Hackerrank
• CodeKata
• Leetcode OJ
• Python Challenge
• Sphere Online Judge
• USACO
• CheckIO
• 1HaskellADay
• CodeFights
• CodeWars
• exercism.io
• Coding Game
• CS Academy
• Programming Praxis
• Hacker Earth
• Geeks for Geeks
• CodeForces
• TopCoder
• /r/dailyprogrammer
• /r/programmingchallenges
• Reddit Programming Challenge
• Codewars
• Exercism.io