Some practice development problems
Problems found on: https://projecteuler.net/ Project Euler’s stated goal is to provide fun and recreational problems for you to solve.
http://codegolf.stackexchange.com/ Stack Exchange has a massive number of user submitted programming puzzles on their code golf site. They range from the outright boring to fairly interesting.
http://www.codeabbey.com/ Code Abbey presents computer programming challenges ranging from Rubik’s Cube to Algae Robot.
http://rosalind.info/problems/locations/ Rosalind has a list of exciting bioinformatics problems to try out.
http://www.spoj.com/ has around 22,000 computer programming problems to choose from.
https://www.reddit.com/r/dailyprogrammer/ has hundreds of computer programming puzzles. Monday’s puzzles are easy. Wednesday’s puzzles are medium difficulty. Friday’s are supposed to be the most challenging.
https://programmingpraxis.com/ about 500 interesting programming challenges.
https://adventofcode.com Practice problems, one per day December