GUIDED PRACTICE
Sliding window
Reuse work across adjacent ranges.
8:00Self-guided practice timer
The timer resets when you leave this page. Save your design separately.Your challenge
Trace the longest unique substring in abcaac.
Your design draft
Clarify assumptions, explain your approach, and test the difficult cases. Save your draft, then compare it with the study notes.
Self-review checklist
Self-guided practice. Automated AI feedback and code execution are not connected.