Leetcode - Longest Repeating Character Replacement

Question

You are given a string s and an integer k. You can choose any character of the string and change it to any other uppercase English character. You can perform this operation at most k times.

Return the length of the longest substring containing the same letter you can get after performing the above operations.

This is asliding_window question.

Idea

• Use a sliding window (use an L and R pointer that start at position 0) (While R < len(s))
• Use a hashmap to keep track of the characters that we’ve seen
• Check if the current sliding window size - count of the most frequent character ≤ k
  • If true:
    • update res
  • Else: Reduce count at [L] Slide L
  • Slide R
• Return res

Solution