Lecture

Implementation of Sets (II)

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In course

CS-108: Practice of object-oriented programming

Les étudiants perfectionnent leurs connaissances en Java et les mettent en pratique en réalisant un projet de taille conséquente. Ils apprennent à utiliser et à mettre en œuvre les principaux types de collections (listes, ensembles, tables associatives), e ...

Description

This lecture focuses on the concrete implementation of sets using a class called S list 7, which stores elements in a list without duplicates. The instructor explains the methods provided by S abstract 7 and the inefficiency of this naive implementation. The lecture covers the size, add, and remove methods, highlighting the importance of the equals method for sets. The instructor also discusses the iterator method and the considerations for implementing it correctly. A test class, S7Test, is used to verify the implementation, emphasizing that while technically correct, the S list 7 class is too inefficient for practical use. The lecture concludes by hinting at a more sophisticated implementation based on hash tables in the next video.

Instructor

Michel Schinz

Teaching & PhD Courses Advanced compiler construction CS-420 Students learn several implementation techniques for modern functional and object-oriented programming languages. They put some of them into practice by developing key parts of a compiler and run time system for a simple functional programming language. Practice of object-oriented programming CS-108 Students improve their knowledge of Java and put it into practice by implementing a sizeable project. They learn how t

Official source

Related concepts (28)

Hash table

In computing, a hash table, also known as hash map, is a data structure that implements an associative array or dictionary. It is an abstract data type that maps keys to values. A hash table uses a hash function to compute an index, also called a hash code, into an array of buckets or slots, from which the desired value can be found. During lookup, the key is hashed and the resulting hash indicates where the corresponding value is stored.

Family of sets

In set theory and related branches of mathematics, a collection of subsets of a given set is called a family of subsets of , or a family of sets over More generally, a collection of any sets whatsoever is called a family of sets, set family, or a set system. A family of sets may be defined as a function from a set , known as the index set, to , in which case the sets of the family are indexed by members of .

Hash function

A hash function is any function that can be used to map data of arbitrary size to fixed-size values, though there are some hash functions that support variable length output. The values returned by a hash function are called hash values, hash codes, digests, or simply hashes. The values are usually used to index a fixed-size table called a hash table. Use of a hash function to index a hash table is called hashing or scatter storage addressing.

Disjoint sets

In mathematics, two sets are said to be disjoint sets if they have no element in common. Equivalently, two disjoint sets are sets whose intersection is the empty set. For example, {1, 2, 3} and {4, 5, 6} are disjoint sets, while {1, 2, 3} and {3, 4, 5} are not disjoint. A collection of two or more sets is called disjoint if any two distinct sets of the collection are disjoint. This definition of disjoint sets can be extended to families of sets and to indexed families of sets.

Hash collision

In computer science, a hash collision or hash clash is when two pieces of data in a hash table share the same hash value. The hash value in this case is derived from a hash function which takes a data input and returns a fixed length of bits. Although hash algorithms have been created with the intent of being collision resistant, they can still sometimes map different data to the same hash (by virtue of the pigeonhole principle). Malicious users can take advantage of this to mimic, access, or alter data.

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Abbreviated Calculation: Structures and Sets

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