15 sites for Programming Practice

I’m a believer in learning by doing. Programming exercises are a useful tool to practice and improve your coding skills. After all, practice makes one, if not perfect, at least pretty darn good. (Yes, I know competitive programming differs from
real-world programming.)

Below is a list of high-quality sites for programming exercises. This is not a comprehensive list since there are countless sites dedicated to coding exercises.

Nevertheless, these 12 sites alone could keep you busy for quite a while.
Project Euler
HackerRank
Reddit /r/dailyprogrammer
LeetCode
Top Coder
Code Forces
CodeChef
Programmr
CoderByte
Timus
HackerEarth
CodinGame

Three honorable mentions

These three are not full-blown automated judge sites or competitive sites, but they are certainly worth mentioning as valuable resources for problem and project ideas.
karan’s Projects
CodeKata
99 problems