grokking_242

class Solution {
   public int maxConsecutiveAnswers(String answerKey, int k) {
       return Math.max(
           longestSubstrAtMostKCharacter(answerKey, 'T', k),
           longestSubstrAtMostKCharacter(answerKey, 'F', k));
   }

   public int longestSubstrAtMostKCharacter(String str, char target, int k) {
       int maxLen = 0;
       int left = 0;
       int count = 0;
       for (int right = 0; right < str.length(); right++) { // enlarge window
           if (str.charAt(right) == target) count++;

           while (count > k) {
               // condition satisfy, shrink window
               if (str.charAt(left) == target) count--;
               left++;
           }
           maxLen = Math.max(maxLen, right - left + 1);
       }
       return maxLen;
   }
}