Meet Allison & Tim
Your AI coaches
Practice coding interviews out loud with real-time voice coaching. Your code actually runs.
Happy Number
Happy Number rewards a clean two-pointer invariant instead of checking every combination. It's a great warm-up that builds invariant-driven scanning without a ton of moving parts. The trap is moving the wrong pointer and silently skipping the real answer.
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.
Desktop required
Sorry — mobile can’t run the editor + tests yet. Email yourself a link to continue on desktop.