Longest Repeating Character Replacement
Finding Longest Subarrays (Standard Sliding Window) DSA practice problem on Onlearn.
Difficulty: medium.
Topics: Longest Repeating Character Replacement Problem, Strings, String Manipulation, Frequency Counting, Sliding Window, Two Pointers, Loops, Optimization, Time Complexity, Space Complexity, Arrays, sliding window, string manipulation, greedy algorithm, frequency counting, two pointer technique, Greedy Approach.
You are given a string s consisting of uppercase English letters, and an integer k. You can perform an operation where you choose any character in the string and change it to any other uppercase English character. You can perform this operation at most k times. Your task is to find the length of the longest substring that contains all repeating letters you can get after performing at most k operations. Input Specification: s: A string consisting of uppercase English letters (1 <= s.length <= 10^5). k: An integer representing the maximum number of operations allowed (0 <= k <= s.length). Output Specification: An integer representing the length of the longest repeating character substring. Constraints: 1 <= s.length <= 10^5 0 <= k <= s.length s consists of only uppercase English letters. Sample Test Cases: Sample 1: Input: s = "ABAB" k = 2 Output: 4 Explanation: Replace the two 'A's with 'B's to get "BBBB" or the two 'B's with 'A's to get "AAAA". In either case, the length of the longest repeating character substring is 4. Sample 2: Input: s = "AABABBA" k = 1 Output: 4 Explanation: The longest substring we can achieve is of length 4. For example, consider the substring "AABA" (from index 0 to 3). With 1 operation, we can change the 'B' to an 'A' to get "AAAA", which has a length of 4.