Bring the challenge to your class.

Introduce it in five minutes, share a class code, and let students continue on their own. Joining your class is optional for them, and free for everyone.

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Closes November 7, 2026 at 11:59 p.m. ET

A five-minute introduction.

Show the homepage, read Problem 1 together and point out how input and output work. That’s enough for students to start. After that they work independently, in class or at home, at their own pace.

See a sample activity

Individual accounts, optional class.

Every student signs up with their own account. They can join your class with your code or link, and they see your name and class before confirming. Students can also skip it, or leave later.

Joining shares only competition progress: display alias, current problem, problems attempted and solved, points and last activity. Never email, code or rankings.

Follow progress, not people.

Your class page lists the students who joined, the problem each one is on, what they’ve solved and their points. A problem view shows where the class tends to get stuck, so you know what to review together.

There are no class rankings or team scores. Each student takes part as an individual.

Sample classroom activity

About ten minutes in class, then students continue on their own. Adjust it to your group.

0:00–1:00
Show the challenge
Open the homepage. It’s free, problems open one at a time, and it closes November 7, 2026 at 11:59 p.m. ET.
1:00–3:00
Read Problem 1 together
Look at the statement, input, output and examples. Ask: what should the program print for the first example? The rules allow a teacher-led walkthrough of Problem 1; later problems follow the independent-work rules.
3:00–4:00
Explain input and output
Programs read from standard input and print only the answer. No prompts like “Enter a number”.
4:00–5:00
Share your class code
Students create their own accounts and can join with your code or link. Remind them joining is optional.
After class
Students continue independently
Check your class page later to see who is stuck on which problem, and review that idea together.

Teaching Resources in your teacher account include an unranked demonstration problem with notes and a ready-to-send student invitation.

Set up a class in a minute.

A teacher account is free. You’ll only see students who choose to join.

Create a teacher account

Read the rules and the privacy notice.