Dictionaries-Hash-Tables-and-Sets
... Elements have almost random order Ordered by the hash code of the key Dictionary relies
...
... Elements have almost random order Ordered by the hash code of the key Dictionary
Blue Border - Courant Institute of Mathematical Sciences
... Multiplication in Zp[x]/(xn-1) takes time O(nlogn) using FFT ...
... Multiplication in Zp[x]/(xn-1) takes time O(nlogn) using FFT ...
Recurrence Relations
... • This collection is universal if for each pair of distinct keys k and q in U, the number of hash functions h in H for which h(k) = h(q) is at most |H|/m. • If we choose our hash function randomly from H, this implies that there is at most a 1/m chance that h(k) = h(q). • This leads to the expect le ...
... • This collection is universal if for each pair of distinct keys k and q in U, the number of hash functions h in H for which h(k) = h(q) is at most |H|/m. • If we choose our hash function randomly from H, this implies that there is at most a 1/m chance that h(k) = h(q). • This leads to the expect le ...
INFOSYS 255 Lecture 16: Hash Tables
... key mod m m is the array size; in general, it should be prime number Floor ((key*someFraction mod 1)*arraySize) Where some fraction is typically 0.618 ...
... key mod m m is the array size; in general, it should be prime number Floor ((key*someFraction mod 1)*arraySize) Where some fraction is typically 0.618 ...
Data Structures for Midterm 2
... • Uses (key, value) with elements sorted by key – For set: key = value ...
... • Uses (key, value) with elements sorted by key – For set: key = value ...
W5Hashing
... Notice how hash values jump around over the range of possible values at what appears to be random. Each of the probe sequences visits all the table locations if the size of the table and the size of the increment are relatively prime with respect to each other. ...
... Notice how hash values jump around over the range of possible values at what appears to be random. Each of the probe sequences visits all the table locations if the size of the table and the size of the increment are relatively prime with respect to each other. ...
HashTables - University of Arizona
... to store the table as an array of linked lists and to keep at each array index the list of values that yield that hash value known as separate chaining Most often the data stored in a hash table includes both a key field and a data field (e.g., social security number and student information). Th ...
... to store the table as an array of linked lists and to keep at each array index the list of values that yield that hash value known as separate chaining Most often the data stored in a hash table includes both a key field and a data field (e.g., social security number and student information). Th ...
ch13hashing
... – Occur when the hash function maps more than one item into the same array location ...
... – Occur when the hash function maps more than one item into the same array location ...
MapADT_HashTables
... Hashing involves transforming data to produce an integer in a fixed range (0..TABLE_SIZE-1) The function that transforms the key into an array index is known as the hash function When two data values produce the same hash value, you get a collision—it happens! Collision resolution may be don ...
... Hashing involves transforming data to produce an integer in a fixed range (0..TABLE_SIZE-1) The function that transforms the key into an array index is known as the hash function When two data values produce the same hash value, you get a collision—it happens! Collision resolution may be don ...
The Map ADT and Hash Tables
... ♦ Hashing involves transforming data to produce an integer in a fixed range (0..TABLE_SIZE-1) ♦ The function that transforms the key into an array index is known as the hash function ♦ When two data values produce the same hash value, you get a collision—it happens! ♦ Collision resolution may be don ...
... ♦ Hashing involves transforming data to produce an integer in a fixed range (0..TABLE_SIZE-1) ♦ The function that transforms the key into an array index is known as the hash function ♦ When two data values produce the same hash value, you get a collision—it happens! ♦ Collision resolution may be don ...
CS2007Ch12C
... All previous searching techniques require a specified amount of time (O(logn) or O(n)) Time usually depends on number of elements (n) stored in the table In some situations searching should be almost instantaneous -- how? ...
... All previous searching techniques require a specified amount of time (O(logn) or O(n)) Time usually depends on number of elements (n) stored in the table In some situations searching should be almost instantaneous -- how? ...
Resetting The CIM \ EIM System “sa” Password Procedure
... 2. a. To verify user_name, and select user_id“save the results for backup. b. “SELECT user_id, user_name, password, case_insensitive_password FROM egpl_user WHERE user_id = 1”. Note: Be sure to save query and results, so that it can be provided for troubleshooting, if there is a problem. 3. a. For B ...
... 2. a. To verify user_name, and select user_id“save the results for backup. b. “SELECT user_id, user_name, password, case_insensitive_password FROM egpl_user WHERE user_id = 1”. Note: Be sure to save query and results, so that it can be provided for troubleshooting, if there is a problem. 3. a. For B ...
security
... Hash functions • Produce fixed-length hash (~32 bits) from variable-length message – It is computationally infeasible to find a message with that hash; in fact one can't determine any usable information about a message with that hash, not even a single bit. – Biometrics usually work the same way! ...
... Hash functions • Produce fixed-length hash (~32 bits) from variable-length message – It is computationally infeasible to find a message with that hash; in fact one can't determine any usable information about a message with that hash, not even a single bit. – Biometrics usually work the same way! ...
Data Structures (810:052) Lecture 20 Name:_________________
... however, then they will always follow the same probe sequence for every collision resolution method that we have seen so far. The probe sequences generated by pseudo-random and quadratic probing (for example) are entirely a function of the home position, not the original key value. This is because f ...
... however, then they will always follow the same probe sequence for every collision resolution method that we have seen so far. The probe sequences generated by pseudo-random and quadratic probing (for example) are entirely a function of the home position, not the original key value. This is because f ...
Hash Tables and Sets
... HashTable. Keep the data in array of lists of keyvalue pairs (LinkedList>[]) with
initial capacity of 16. When the hash table load runs
...
... HashTable
Oracle`s Business Strategy: Maximizing Your Sales Leverage
... • Trie’s (Text retRieval data structure) can be used deterministically to find the closest match in a dictionary of words. Unsuccessful searches terminate quickly. Searches are usually tolerant and allows ...
... • Trie’s (Text retRieval data structure) can be used deterministically to find the closest match in a dictionary of words. Unsuccessful searches terminate quickly. Searches are usually tolerant and allows ...
PPT
... Review: Choosing A Hash Function ● Choosing the hash function well is crucial ■ Bad hash function puts all elements in same slot ■ A good hash function: ○ Should distribute keys uniformly into slots ○ Should not depend on patterns in the data ...
... Review: Choosing A Hash Function ● Choosing the hash function well is crucial ■ Bad hash function puts all elements in same slot ■ A good hash function: ○ Should distribute keys uniformly into slots ○ Should not depend on patterns in the data ...
Review – Hash Tables with Chaining
... The header file hashtable.h that defines those required functions and data structures can be found on the course website. ...
... The header file hashtable.h that defines those required functions and data structures can be found on the course website. ...
Hashing
... If two cluster are only separated by one entry, then inserting one key into a cluster can merge the two clusters together. Thus, the cluster size can increase drastically by a single insertion. This means that the performance of insertion can deteriorate drastically after a single insertion. ...
... If two cluster are only separated by one entry, then inserting one key into a cluster can merge the two clusters together. Thus, the cluster size can increase drastically by a single insertion. This means that the performance of insertion can deteriorate drastically after a single insertion. ...
CS 3114 Data Structures and Algorithms Homework 3: Hashing 1
... The home slot of a record depends only on the key, the hash function, and the size of the table. The collision resolution strategy does not come into play in selecting the home slot. Therefore the number of primary collisions will be same no matter what collision resolution strategy is used. b) [10 ...
... The home slot of a record depends only on the key, the hash function, and the size of the table. The collision resolution strategy does not come into play in selecting the home slot. Therefore the number of primary collisions will be same no matter what collision resolution strategy is used. b) [10 ...
Data Structures (810:052) Lecture 24 Name:_________________
... Check next spot (counting circularly) for the first available slot, i.e., (home address + (rehash attempt #)) % (hash table size) Check a square of the attempt-number away for an available slot, i.e., (home address + ((rehash attempt #)2 +(rehash attempt #))/2) % (hash table size), where the hash ta ...
... Check next spot (counting circularly) for the first available slot, i.e., (home address + (rehash attempt #)) % (hash table size) Check a square of the attempt-number away for an available slot, i.e., (home address + ((rehash attempt #)2 +(rehash attempt #))/2) % (hash table size), where the hash ta ...
The NDN Forwarding Plane
... ◦ compiled using gcc-4.4.1 with optimization level -O4. ◦ The core component, ccnd, is configured with all default environment variable values. ◦ The Content Store size is set at the default value of 50, 000 ...
... ◦ compiled using gcc-4.4.1 with optimization level -O4. ◦ The core component, ccnd, is configured with all default environment variable values. ◦ The Content Store size is set at the default value of 50, 000 ...
U.C. Berkeley — CS270: Algorithms Lectures 13, 14 Scribe: Anupam
... are drawn drawn from a universe of size n. Realtime data like server logs, user clicks and search queries are modeled by streams. The available memory is much less than the size of the stream, so a streaming algorithm must process a stream in a single pass using sublinear space. We consider the prob ...
... are drawn drawn from a universe of size n. Realtime data like server logs, user clicks and search queries are modeled by streams. The available memory is much less than the size of the stream, so a streaming algorithm must process a stream in a single pass using sublinear space. We consider the prob ...
Lecture Note 10
... – Find record/empty slot starting at index = h(key) (use resolution policy if necessary) ...
... – Find record/empty slot starting at index = h(key) (use resolution policy if necessary) ...
Rainbow table
A rainbow table is a precomputed table for reversing cryptographic hash functions, usually for cracking password hashes. Tables are usually used in recovering a plaintext password up to a certain length consisting of a limited set of characters. It is a practical example of a space/time trade-off, using less computer processing time and more storage than a brute-force attack which calculates a hash on every attempt, but more processing time and less storage than a simple lookup table with one entry per hash. Use of a key derivation function that employs a salt makes this attack infeasible.Rainbow tables are an application of an earlier, simpler algorithm by Martin Hellman.