Algoverse_adesh_8

class Solution:
        def characterReplacement(self, s: str, k: int) -> int:

            l = 0
            frequency = {}
            longest = 0
            for i in range(len(s)):

                if not s[i] in frequency:
                    frequency[s[i]] = 0
                frequency[s[i]] += 1
                count = i - l + 1
                if count - max(frequency.values()) <= k:
                    longest = max(longest, count)

                else:
                    frequency[s[l]] -= 1
                    if not frequency[s[l]]:
                        frequency.pop(s[l])
                    l += 1

            return longest