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PATTERN 03 · 3 PROBLEMS

Sliding window

Maintain one contiguous range and repair it as the right edge expands.

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MASTER KEYExpand to learn; shrink to restore the rule.
0OF 3
RECALLED
RECOGNITION SIGNAL

A duplicate invalidates only the prefix through its previous occurrence.

01
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Longest Substring Without Repeating Characters

A duplicate invalidates only the prefix through its previous occurrence.

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02
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Longest Repeating Character Replacement

Window cost is length minus its most frequent character count.

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03
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Minimum Window Substring

A window becomes valid when all required kinds reach their needed counts.

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