Longest Repeating Character Replacement

424. Longest Repeating Character Replacement

Solutions

Sliding Window with tolerance

1. Keep pointer start and curr, a dictionary of num_occurance and max_occurance
2. If curr - start + 1 - max_occurance > tolerance
   • Move start to next
   • Update num_occurance num_occurance[ord(s[start]) - ord('A')] -= 1

     No need to update max_occurance because we only expect window ≥ max_occurance + k, thus start will only be updated when max_occurance is updated by s[curr]

3. return l or max_occurance + tolerance