Advent of Code
adventofcode.comAnnual programming puzzles released daily every December
Dev Toolsprogramming-puzzlescoding-challengeadvent-calendarcompetitive-programmingcommunityeducation

About
Advent of Code is an annual online event featuring a series of daily programming puzzles released throughout December, similar to an advent calendar. Participants solve challenges using any programming language of their choice, often competing on leaderboards. It is free to participate and draws a large community of developers each year.
Problem
Developers lack a fun, structured way to practice problem-solving skills during the holiday season.
For
software developers and programming enthusiasts
How it works
Each day in December a new two-part puzzle is unlocked, and participants submit solutions written in any language to earn stars on a global or private leaderboard.
Business model
free
Status
launched