Start coding. See how far you go.
A free programming challenge designed with high-school students in mind. It starts with approachable problems, and each one you solve opens the next.
Free to enter · Closes November 7, 2026, 11:59 p.m. ET
Start with something small.
Everyone begins with the same first problem: read a few numbers, print one answer. Solve it completely and the next problem opens. Each one asks a little more of you.
Every test counts.
Your code is checked against hidden tests, and each one you pass is worth 100 points. Pass 7 of 10 and you keep 700. Improve it later and only the difference is added. Your best submission always counts.
Understand the ideas behind the code.
The Algorithm Library is an original textbook written for this challenge. Read each chapter in your browser or download the PDF, with worked examples, diagrams and practice exercises. New chapters are added over time.
Bring your class along.
Teachers can create a class code in a minute. Students still take part with their own accounts, and joining a class is optional. It simply lets a teacher follow progress on the problems.
Questions
More detail is in the rules.
Ready when you are.
Create a free account and start with Problem 1. It takes about a minute.
Join the challenge