class Solution:
  def findLength(self, text, k):
      max_length = float('-inf')
      freq = {}
      j = 0 
      
      most_freq_char = float('-inf')

      for i in range(len(text)):
        # update all characters frequencies
        char = text[i]
        freq[char] = freq.get(char, 0)
        freq[char] += 1

        # track the most frequent character 
        most_freq_char = max(most_freq_char, freq[char])

        # total_len = the total length of the window 
        # can_be_discarded_len = the length of the characters other than the most frequent character 
        # can_be_discarded_len is what we use for knowing <= or > k 
        total_len = i - j + 1
        can_be_discarded_len = total_len - most_freq_char
        
        if can_be_discarded_len <= k:
          max_length = max(max_length, total_len)

        else:
          while can_be_discarded_len > k:
            # decrees the frequencies
            freq[text[j]] -= 1
            # move j forward
            j += 1
            # recalculate the remaining characters that has to be discarded from the left
            can_be_discarded_len -= 1

      return max_length