Longest Repeating Character Replacement LeetCode solution in Python

1
class Solution:
2
    def characterReplacement(self, s: str, k: int) -> int:
3
        # Initialize variables
4
        window_start = 0
5
        max_length = 0
6
        max_count = 0
7
        char_count = {}
8

9
        # Traverse the string s
10
        for window_end in range(len(s)):
11
            # Increment the count of the current character
12
            char_count[s[window_end]] = char_count.get(s[window_end], 0) + 1
13
            # Update the maximum count seen so far
14
            max_count = max(max_count, char_count[s[window_end]])
15

16
            # Shrink the window if required
17
            if window_end - window_start + 1 > max_count + k:
18
                char_count[s[window_start]] -= 1
19
                window_start += 1
20

21
            # Update the maximum length of the substring with repeating characters seen so far
22
            max_length = max(max_length, window_end - window_start + 1)
23

24
        return max_length