Leetcode 567. Permutation in String
Check whether any substring of s2 of length |s1| is a permutation of s1 (i.e., has the same character multiset). The core challenge is to do this efficiently—typically via a sliding-window with constant-size (26-letter) frequency comparisons for strings up to length 10^4.
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Apple
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Mid March, 2026
Apple
Senior
Given two strings `input` and `pattern`, return `true` if `pattern` contains a permutation of `input` as a substring. In other words, return true if any anagram of `input` appears as a contiguous substring in `pattern`.
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