Meet Allison & Tim
Your AI coaches
Practice coding interviews out loud with real-time voice coaching. Your code actually runs.
Start Part 1 to unlock your next challenge
Contains Duplicate
Contains Duplicate is a classic scan-and-record problem: the right bookkeeping beats brute force. It's a great warm-up that builds data-structure instincts without a ton of moving parts. Watch your edge cases around repeats, and be clear about what your map is storing.
Meet Allison & Tim
Your AI coaches
Practice coding interviews out loud with real-time voice coaching. Your code actually runs.
Desktop required to run this problem
StrongYes runs real code + tests in a desktop editor. Mobile is view-only for now, so you can’t start this here. Sorry about that — email yourself a link and pick it up on your computer.
Start Part 1 to unlock your next challenge
Desktop required
Sorry — mobile can’t run the editor + tests yet. Email yourself a link to continue on desktop.