Permutation in String 25 XP Medium

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Given two strings s1 and s2, return True if s2 contains a permutation of s1.

In other words: does any substring of s2 contain exactly the same characters as s1 (same frequency)?

s1 = 'ab', s2 = 'eidbaooo'
# Output: True — 'ba' is a permutation of 'ab'

Approach: Use a fixed-size sliding window of size len(s1) over s2. Compare character frequency counts using hash maps.

📋 Instructions

Implement `check_inclusion(s1, s2)` that checks if any permutation of s1 exists as a substring in s2. Test with: - `check_inclusion('ab', 'eidbaooo')` → True - `check_inclusion('ab', 'eidboaoo')` → False Print both results.

Count s1 characters. Slide a window of size len(s1) over s2, maintaining a count of window characters. If counts match, return True.

🧪 Test Cases

Input

check_inclusion('ab', 'eidbaooo')

Expected

True

Boolean check

Input

check_inclusion('ab', 'eidboaoo')

Expected

False

Boolean check

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main.py

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Output

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