← All coding problems
Longest Repeating Character Replacement
mediumSliding Window+20 XPTime limit 2s
You may change at most k characters of the string into any other uppercase letter. What is the length of the longest substring that can be made of one repeated letter?
Input:
- line 1:
s(uppercase English letters) - line 2:
k
Output: the maximum length.
Constraints: 1 ≤ length of s ≤ 10⁵, 0 ≤ k ≤ length of s.
Think about it: a window is fixable when window length − (count of its most frequent letter) ≤ k. Slide the window and keep letter counts.
Sample input 1
ABAB 2
Sample output 1
4
Sample input 2
AABABBA 1
Sample output 2
4
📖 Stuck? Learn the pattern
Read input from standard input and print the answer to standard output. Your code runs in a secure sandbox against the samples (Run) and hidden tests (Submit).