Sliding Window • Intermediate • 20 min
Longest Substring Without Repeating Characters
How to notice that the problem asks for a window that expands and contracts, not a full restart at every repetition.
Practice problems with walkthroughs, hints, and solutions.
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Sliding Window • Intermediate • 20 min
How to notice that the problem asks for a window that expands and contracts, not a full restart at every repetition.
Sliding Window • Advanced • 30 min
How to turn "does it contain everything?" into a satisfaction condition and shrink the window only while it stays valid.