PPT-Hash Tables: Handling Collisions

CSE 373 Data Structures and Algorithms Thanks to Kasey Champion Ben Jones Adam Blank Michael Lee Evan McCarty Robbie Weber Whitaker Brand Zora Fung Stuart Reges Justin Hsia Ruth Anderson and many others for sample slides and materials . Spencer Dawson. Summary. What are rainbow tables?. A time and memory tradeoff in password cracking.. A piecewise approach to one-way hashes. What are the advantages/disadvantages. Best uses. Limitations. Lecture 3. Sets. A . set. is simply a collection of elements. Unlike lists, elements are not ordered. Very abstract, general concept with broad usefulness:. The set of all Google search queries from the past 24 hours. Motivating Applications. Large collection of datasets. Datasets are dynamic (insert, delete). Goal: efficient searching/insertion/deletion. Hashing is ONLY applicable for exact-match searching. Direct Address Tables. Comp 550. Dictionary . Dictionary:. Dynamic-set data structure for . storing items indexed using . keys. .. Supports . operations: Insert, Search, and . Delete . (. take . O. (1) time. ). .. Applications:. Message Authentication Codes. Sebastiaan. de Hoogh, . TU/e. Cryptography 1. September 12, 2013. Announcements. Until this morning 50 students handed in 43 pieces of . homeworks. . (only 7 pairs). BUT: . Passwords stored in computers are changed from their plain text form to an encrypted value.. These values are called hashes, and there is a unique plain text value for every hash.. A rainbow table is a lookup table offering a time-memory tradeoff used in recovering the plaintext password from a password hash generated by a hash function . Martin Åkerblad. William . bruce. What is . Hashing?. Index. Key. 1. 2. 3. 4. 5. 6. 7. Key. 56. 84. 23. 42. 71. 97. 55. Hash. . function. 56. 42. 71. 23. 84. 55. 97. Value. When to use hashing.. Quick searching in large databases. Miles. Jones. MTThF. 8:30-9:50am. CSE 4140. September 1, 2016. Element Distinctness: WHAT. Given list of positive integers a. 1. , a. 2. , …, a. n. decide whether all the numbers are . distinct or whether there is a . CIS 606. Spring 2010. Hash tables. Many applications require a dynamic set that supports only the . dictionary . operations . INSERT. , SEARCH, and DELETE. Example: a symbol table in a compiler.. A hash table is effective for implementing a dictionary.. Plan. I spent the last decade advising on numerous cases where hash tables/functions were used. A few observations on . What data structures I’ve seen implemented and where. What do developers think, were they need help. Hash Tables. . . 0. 1. 2. 3. 4. 451-229-0004. 981-101-0002. 025-612-0001. © 2014 Goodrich, Tamassia, Godlwasser. Presentation for use with the textbook . Data Structures and Algorithms in Java, 6. . Outline. Discuss what a hash method does. translates a string key into an integer . Discuss a few strategies for implementing a hash table. linear probing. quadratic probing. separate chaining hashing. n. . . [from the . techspeak. ] (var. ‘hash clash’) . When used of people, signifies a confusion in associative memory or imagination, especially a persistent one.” . . -. The Hacker's Dictionary . Instructor: Lilian de Greef Quarter: Summer 2017 CSE 373: Data Structures and Algorithms Lecture 6: Finishing Amortized Analysis; Dictionaries ADT; Introduction to Hash Tables Today: Finish up Amortized Analysis