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Analytics: Longest Unique Session Window
Also known as: Longest Substring Without Repeating Characters
This one is the sliding window pattern: grow, shrink, and maintain just enough state to stay linear. Interviewers love it because it reveals your stateful scanning and your edge-case discipline. Once your window update rules are consistent, you get linear time almost for free.
Learn this pattern
Sliding Window Algorithm
Sliding window processes arrays or strings by moving a window through the data, updating results incrementally instead of recalculating from scratch. Reach for it when you see "contiguous subarray," "longest/shortest substring," or "at most K distinct."
Meet your coaches
Talk through the problem while you code. Signed-in reps become prep memory for the next session.
Chat with Fin or Coco right now on mobile.
Start talking through the problem here. Switch to desktop when you're ready to code and run tests.
Start coaching sessionStart a coached rep now. Sign in before or after the session so StrongYes can save what you struggled with to your prep memory.
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Desktop required
Sorry - mobile cannot run the editor and tests yet. Use the next step below or email yourself a link to continue on desktop.
Sliding Window Algorithm gives you a useful next rep while you are still on your phone.