567 - Permutation in String

Given two strings s1 and s2, write a function to return true if s2 contains the permutation of s1.
In other words, one of the first string's permutations is the substring of the second string.

Example 1:

Input: s1 = "ab" s2 = "eidbaooo"
Output: True
Explanation: s2 contains one permutation of s1 ("ba").

Example 2:

Input:s1= "ab" s2 = "eidboaoo"
Output: False


Note:

The input strings only contain lower case letters.
The length of both given strings is in range [1, 10,000].
Accepted

from collections import defaultdict


class Solution:
    def checkInclusion(self, s1: str, s2: str) -> bool:
        target, window = defaultdict(int), defaultdict(int)
        left, right = 0, 0
        match = 0
        for c in s1:
            target[c] += 1

        while (right < len(s2)):

            c = s2[right]
            if c in target:
                window[c] += 1
                if window[c] == target[c]:
                    match += 1

            right += 1

            while (right - left + 1 > len(s1)):
                if match == len(target):
                    return True
                c = s2[left]
                left += 1

                if c in window:
                    if window[c] == target[c]:
                        match -= 1

                    window[c] -= 1
        return False