Maximum Sub-String after at most K changes
Medium Accuracy: 49.19% Submissions: 427 Points: 4

We have a string s of length n, which consist only UPPERCASE characters and we have a number k (always less than n and greater than 0). We can make at most k changes in our string such that we can get a sub-string of maximum length which have all same characters.

Example 1:

Input: s = "ABAB", k = 2
Output: 4
Explanation: Change 2 'B' into 'A'.


Example:

Input: s = "ABCD", k = 1
Output: 2
Explanation: Change one 'B' into 'A'.


You don't need to read print anything. Your task is to complete the function characterReplacement() which takes s and k as input parameter and returns the maximum length of sub-string after doing k changes.

Expected Time Complexity: O(n)
Expected Space Complexity: O(26)

Constraints:
1 <= n <= 104

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