📘

Longest Repeating Character Replacement

Given a string s and an integer k, you can choose any character and change it to any other uppercase English letter at most k times.

Return the length of the longest substring containing the same letter after performing at most k replacements.

Input:

AABABBA
1

Output:

Reasoning:

We start with the input string AABABBA and the replacement limit k = 1.
We try to find the longest substring with the same letter after at most k replacements. The substring AABBB can be formed by replacing one A with a B, resulting in a substring of length $4$ with the same letter B if we consider AABBB as BBBB after replacement, but since we are considering AABABBA we look at AABB and BBBA and see AABB can become AAAA or BBBB with one replacement.
Considering all possible substrings, we find that the longest one with the same letter after at most 1$ replacement is of length $4$, which can be achieved by replacing one character in AABBto getAAAAor inBBBAto getBBBB`.
The final output is $4$ .

Editor

Python 3.13.1

0/0

Run code to see test results.

📘