During March 2025, Elavl developed a substring length constraint feature for the CodingTestStudy2/Daily_Morning_Coding_Test repository. The solution computes the maximum length of a substring where each character appears at most twice, addressing string-constraint validation for coding test evaluations. Elavl applied a sliding window algorithm with two pointers and a HashMap in Java, achieving O(n) time and O(K) space complexity. This approach improved the platform’s throughput and maintainability by enabling faster, scalable candidate solution assessments. The work demonstrated depth in algorithm design and code quality, with no major bugs reported, reflecting careful implementation and attention to platform stability.