# 567. Permutation in String from collections import Counter """ given two strings 's1 s2' return true if 's2' contains a permutation of 's1' or false otherwise. in other words, return true if one of 's1's permutations is in the substring of 's2' """ class Solution(object): def checkInclusion(self, s1, s2): """ :type s1: str :type s2: str :rtype: bool """ cnt, n, match = Counter(s1), len(s1), 0 for i in range(len(s2)): if s2[i] in cnt: if not cnt[s2[i]]: match -= 1 cnt[s2[i]] -= 1 if not cnt[s2[i]]: match += 1 if i >= n and s2[i - n] in cnt: if not cnt[s2[i - n]]: match -= 1 cnt[s2[i - n]] += 1 if not cnt[s2[i - n]]: match += 1 if match == len(cnt): return True return False if __name__ == "__main__": obj = Solution() print(obj.checkInclusion(s1="ab", s2="eidbaooo")) print(obj.checkInclusion(s1="ab", s2="eidboaoo"))