Lecture Data structures & algorithms: Maps & hash functions - Đào Trung Kiên

In the realm of computer science, efficient data organization is paramount for developing robust and performant software systems. This document introduces fundamental concepts surrounding "Maps" and "Hash Functions", two critical components within "Data Structures" and "Algorithms" that enable rapid data access and manipulation. We delve into how these structures generalize array indexing by facilitating the storage and retrieval of information based on arbitrary "key-value pairs", moving beyond simple numeric indices. The discussion sets the stage for understanding the underlying mechanisms that power efficient data lookup, a cornerstone for various computational tasks and applications.

Sinh viên ngành Khoa học Máy tính, Kỹ thuật Phần mềm, hoặc bất kỳ ai đang học về Cấu trúc Dữ liệu và Giải thuật, và các nhà phát triển phần mềm muốn hiểu sâu về cách thức hoạt động của các cấu trúc dữ liệu cơ bản.

This academic module provides a comprehensive overview of "Maps" (also known as "Dictionaries" or "Associative Arrays") and "Hash Functions", essential concepts in the study of "Data Structures" and "Algorithms". It begins by positioning maps as a generalization of traditional arrays, allowing for indexing not just by integers but by diverse data types through "key-value pairs". Various terminologies across programming languages like C++, Java, Python, and Ruby are clarified, highlighting the pervasive nature of this data structure. The core functionalities such as inserting, removing, and finding elements by their "keys" are detailed. A significant portion is dedicated to "Hash Functions", explaining their role in mapping keys to specific memory locations to achieve efficient data retrieval. The document illustrates "collision resolution" techniques, specifically "chaining", where multiple keys hashing to the same index are managed effectively. Practical applications span from simple address books to complex data lookup systems. Furthermore, the material includes C-like declarations and operational prototypes for a `STR_MAP` (string map), demonstrating the programmatic implementation of initialization, insertion, searching, and deletion, providing a concrete understanding of how these theoretical concepts translate into executable code. This foundational knowledge is crucial for anyone building scalable and efficient software, offering insights into optimizing data management.