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mediumGrind 75

Longest Repeating Character Replacement

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.

Arrays & HashingStringTwo PointersSliding Window
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1Find Longest Substring with K Replacementsmedium
Based onLeetCode

Desktop required

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