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You are given a string s consisting of uppercase English letters and an integer k representing the maximum number of character replacements you can perform.
In one replacement operation, you can select any character in the string and change it to any other uppercase English letter. Your goal is to find the length of the longest contiguous segment of the string that contains only identical characters after performing at most k replacement operations.
The key insight is that you want to maximize the length of a substring where all characters can be made the same by replacing at most k characters. This involves strategically choosing which characters to keep and which to replace within a window of consecutive characters.
Return the maximum length of such a uniform segment achievable.
s = "ABAB"
k = 24We can replace the two 'A' characters with 'B' to get "BBBB", or replace the two 'B' characters with 'A' to get "AAAA". Either way, the entire string of length 4 becomes uniform.
s = "AABABBA"
k = 14We can replace the middle 'A' (at index 3) with 'B' to transform the string into "AABBBBA". This creates a uniform segment "BBBB" of length 4. Alternatively, other replacement strategies might yield the same maximum length.
s = "AAAA"
k = 24The string is already uniform with all 'A' characters. Even though we have 2 replacement operations available, no changes are needed. The maximum uniform segment length is 4.
Constraints