Contributed foundational problem-solving features to the DaleStudy/leetcode-study repository, focusing on efficient Python implementations for classic algorithmic challenges. Developed a duplicate detection function using dictionary-based logic to achieve O(n) performance, and implemented a Two Sum solution leveraging hash maps for rapid index retrieval. Enhanced code maintainability by adding explicit time-complexity notes and improving file formatting, including readability fixes such as ensuring proper newlines. Demonstrated practical skills in algorithm analysis, data structures, and file formatting, while maintaining clear commit messages and repository hygiene. The work established a scalable base for future contributions and reduced onboarding friction for new collaborators in the project.