Available question text
Find the length of the longest substring of a lowercase string s such that every character in that substring appears at least k times. The core challenge is to efficiently locate maximal contiguous segments that meet the per-character frequency constraint (often leveraging the fact the alphabet is only 26 letters).
Related questions
Continue with questions that share topics or the same question type.
- Longest Substring Without Repeating Characters
Coding · Hash Table · Sliding Window · String
- Longest Repeating Substring
Coding
- Longest Substring of One Repeating Character
Coding
- Longest Substring with At Most K Distinct Characters
Coding · Hash Table · Sliding Window · String
Sources · 1 reference
These records explain where the question appears. A company tag or candidate report does not guarantee a future interview question.
Hello Interview · 1 record
No company association
Leetcode 395. Longest Substring with At Least K Repeating Characters
Reported date not specified · 0 source reports
Source snapshot: Nov 12, 2026
View source