Foundational Concepts in Data Structures and Algorithms

Notes

Summary of Data Structures and Algorithms Course by Sheldon Chai This comprehensive course covers essential data structures, algorithmic patterns, and problem-solving strategies commonly encountered in coding interviews. The instructor, Sheldon Chai, systematically breaks down foundational concepts, practical implementations, and efficiency considerations, providing clear examples and code walkthroughs. Core Concepts and Data Structures • Arrays • Linear, ordered collections stored in contiguous memory. • Offer O(1) time complexity for random access by index. • Insertion/deletion in the middle requires shifting elements, leading to O(n) complexity. • Commonly used for traversing sequences, implementing sliding windows, prefix sums, and two-pointer techniques. • Strings • Immutable arrays of characters in most languages. • Modifying strings creates new copies, which can cause inefficiencies (e.g., concatenation in loops results in O(n²) time). • Best practice: build strings using lists of characters and join afterward for O(n) efficiency. • Frequently appear in interview problems involving substrings, anagrams, and pattern matching, often solvable using sliding window or two-pointer...