Leetcode 424 step 2

424_longest_repeating_character_replacement.py

    def calculate_length(self, diffs: List[int], k: int) -> int:
        """Calculate maximum sequence length based
        on the differences between character positions

        Args:
            diffs (List[int]): List of position differences
            k (int): Number of characters to replace

        Returns:
            int: Maximum length of replacement
        """
        behind, ahead = 0, 0
        current_k = diffs[0]
        max_length = 0

        while ahead < len(diffs):
            if current_k <= k:
                ahead += 1
                if ahead == len(diffs):
                    break
                current_k += diffs[ahead]
            else:
                behind += 1
                current_k -= diffs[behind]
            length = ahead - behind + current_k
            if length > max_length and current_k <= k:
                max_length = length

        return max_length