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Every problem has a rating. So do you.

CodeLeague is where students get good at programming. Problems at your level for AP Computer Science A or USACO, a studio for making games, and friends to race, all in Java or Python, right in your browser.

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Free to start. Sign in with Google. Under 13? A parent says yes first.

Problem

Choose two fields

Complete searchUSACO Bronze

900problem rating

Accepted · 10 of 10 tests

Your rating

781+39

Three ways in

  • Train

    A problem at your level, picked for the exam you’re working toward. Win on your first try and your rating climbs.

    Start training

  • Make

    Build games with blocks in the Studio, and see the real Java underneath. Program a robot on a field. Share what you make.

    Open the Studio

  • Play together

    Race a friend to solve one problem. Team up in a robot arena. Play games other students made, against each other online.

    Find a friend to play

Why learn to code when AI can write it?

Because someone still has to know what good code is. AI makes people who understand programs faster. It doesn’t make understanding them optional.

  1. Knowing what to ask for. Breaking a problem into pieces is the real skill, and it’s exactly what AI needs from you.
  2. Reading what comes back. AI writes plenty of code that looks right and isn’t. You can only catch it if you can read it.
  3. Fixing what breaks. Debugging is working out what a program really does, step by step. That gets more valuable, not less.
  4. Doing it yourself when it counts. AP Computer Science A and USACO test what you can do on your own.

Train for the exam in front of you

Pick what you are working toward. Your problems follow what that exam asks most, and you can see where you stand in each part of it.

AP Computer Science A

The College Board exam in Java, taken in May. Revised for 2026 into four units.

Length
3 hours
Questions
42 multiple choice, 4 free response
Language
Java
Format
Fully digital

Three hours

  1. Multiple choice 42 questions
  2. Free response 4 questions

Your score

  1. Multiple choice 55%
  2. Free response 45%

The four free-response questions

  1. Methods and control 7 points
  2. Class design 7 points
  3. ArrayList data 5 points
  4. 2D array 6 points

How we train for it. Problems weighted the way the exam is, from conditions and loops to classes and 2D arrays, all in Java. Your Python practice does not count toward it.

Train for AP CSA More about AP CSA

USACO Bronze

The first division of the USA Computing Olympiad. Free online contests through the season.

Length
4 hours, once you start
Problems
Usually 3
Languages
C, C++, Java or Python
Window
Friday to Monday

Your four hours

  1. Problem 1
  2. Problem 2
  3. Problem 3

The tests behind one problem

  1. Sample
  2. Tests you never see

The divisions

  1. Bronze Everyone starts here
  2. Silver
  3. Gold
  4. Platinum

How we train for it. Every past Bronze problem taken apart into the skills it needs, and short problems for each skill on its own, in Java or Python.

Train for USACO More about USACO

How training works

  1. Pick a goal

    AP Computer Science A, USACO Bronze or Silver, or the Java foundations underneath them.

  2. Get a problem at your level

    Each one is rated by how players do on it. You get the one that fits you, in the part you most need.

  3. Solve it in your browser

    Write Java or Python, run the examples, then submit. It is judged on hidden tests in seconds.

  4. Watch your rating move

    Your first try at a problem counts. Win and your rating climbs, in the skill, the exam and the language.

Stuck is where the learning happens

Plenty of students know the technique and still don’t see how to start. So help comes in steps, and you take only as much as you need.

  • Break it down marks each part of the problem in place: what is asked, what you are given, the limits, the cases to watch.
  • Hints come one at a time. The first two help you read. The last two give more away, so that problem stops counting toward your rating.
  • Teach me how builds the solution with you a step at a time, saying which part of the problem each step solves, right into your own code.

Hard problems are small skills, combined

A USACO problem is rarely one idea. It is two or three small skills used together. We took apart all 140 past Bronze problems to find which skills come up most, and built short problems and narrated lessons for each one. Get quick at each skill on its own, and the combination stops being the hard part.

See the problems taken apart
What recent USACO Bronze problems needed most
  1. Spotting the trick 27%
  2. Numbers and math 14%
  3. Complete search 13%
  4. Lists and maps 8%
  5. Greedy thinking 8%

Java or Python. Your choice, and it counts.

Most problems can be solved in either, with a starting point in each. Lessons and robots switch too. A win counts toward the skill, which is about the idea, and toward the language you wrote it in. The AP goal counts Java only, because the exam is in Java.

207 problems to train on 140 past Bronze problems taken apart 15 narrated lessons and exam guides

For parents and teachers

CodeLeague is built for students, and is careful with them.

  • Students 13 and up sign in with Google. Younger students join with a parent’s permission, and the parent can see how they’re doing or turn their account off.
  • Other students only ever see a made-up name and a rating. Never a real name or an email address.
  • Shared projects are read over before anyone else sees them, and a child’s can’t say who or where they are.
  • We do not show advertising and we do not sell anyone’s information.
  • Student code is never used to train AI models.
  • Read the privacy policy or the terms of use.

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