Longest Repeating Character Replacement

Medium

Given a string s of uppercase English letters and an integer k, you may replace at most k characters with any uppercase letter. Return the length of the longest substring containing a single repeated letter you can obtain.

Example 1

Input:  s = "ABAB", k = 2
Output: 4

Example 2

Input:  s = "AABABBA", k = 1
Output: 4

Constraints

• 1 <= s.length <= 10^5
• s consists of uppercase English letters.
• 0 <= k <= s.length