Hash table is a data structure in which keys are mapped to array positions by a hash function. The process of mapping the keys to appropriate locations in a hash table is called hashing. Hash functions are used to reduce the number of collisions. i. Mention the methods to minimize collision. ii. Explain the advantage of using double hashing over linear and quadratic probing techniques. Load the keys given below in a hash table of size 7 in the same order using chaining with the hash function h(key)= key % 7. Show graphically how collisions are resolved using chaining in this particular case.

Hash table is a data structure in which keys are mapped to array positions by a hash function. The process of mapping the keys to appropriate locations in a hash table is called hashing. Hash functions are used to reduce the number of collisions. i. Mention the methods to minimize collision. ii. Explain the advantage of using double hashing over linear and quadratic probing techniques. Load the keys given below in a hash table of size 7 in the same order using chaining with the hash function h(key)= key % 7. Show graphically how collisions are resolved using chaining in this particular case.

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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code in python attached please Define a hash table with an associated hash function ℎ(?)h(k) mapping keys ?k to their associated hash value. b) In simple uniform hashing, each key is assumed to have equal probability to map to any of the hashes in a given table of size m. Given an open-address table of size 500500 and 22 random keys, what is the probability that they hash to the same value? What is the probability that they hash to different values?
1. Draw the 11-entry hash table that results from using the hash function h(i)=(3i+5) mod 11, to hash the keys 12, 44, 13, 88, 23, 94, 11, 39, 20, 16, and 5, assuming collisions are handled by separate chaining. a) What is the result of the previous exercise, assuming collisions are handled by linear probing? b) Show the result of the first question, assuming collisions are handled by quadratic probing, up to the point where the method fails. c) What is the result of the first question, when collisions are handled by double hashing using the secondary (or auxiliary) hash function H'(k)=7-(k mod 7)?
Answer the following ture or false question 1. The 9-entry hash table that results from using the hash function, h(i) = (2i+7) mod 9, to hash the keys 12, 5, 13, 4, 10, 19, 8, 3, and 28, assuming collisions are handled by linear probing as follows: 0 1 2 3 4 5 6 7 8 10 19 3 28 12 8 13 4 5 Group of answer choices True False 2. Here is how the built-in sum function can be combined with Python’s comprehension syntax to compute the sum of all numbers in an n x n data set, represented as a list of lists: sum(sum(subset) for subset in data) Group of answer choices True False 3. Here is the comparison for asymptotic growth rate: (logn) < (n) < (nlogn) < (n^2) < (n^3) < (2^n) Group of answer choices True False 4. Here is the Python’s list comprehension syntax to produce the list of this 26 characters ['a', 'b', 'c', ..., 'z']: [chr(k) for k in range(97, 123)] Group of answer choices True False
python In simple uniform hashing, each key is assumed to have equal probability to map to any ofthe hashes in a given table of size m. Given an open-address table of size 100 and 2random keys, what is the probability that they hash to the same value? What is theprobability that they hash to different values?
1. Consider an open hash (that is, one that deals with collisions by using a linked list) with a million entries. The hash algorithm takes 200ns to run, each comparison of objects takes 10ns, and everything else involved in the lookup takes trivial time. How large does the hash table need to be to use less time on chained comparisons than on the initial hash lookup? (Remember that you always have to compare once.)
22 Consider a hash table with size m=7, fill the following items in the table if the hash function used is (6k-5) mod m. AAB, ABA,CDF,STW,YZQ,PFG (ASCII code) . Then count the number of collisions and solve the collision ( if possible) using one of the methods studied
Consider a OBHTin which the keys are student identifiers (strings of 6 digits). Assume the following number of buckets and hash function: m = 100; hash(id) = first two digits of id Starting with an empty hash table, show the effect of successively adding the following student identifiers: 000014, 990021, 990019, 970036, 000015, 970012, 970023. Use following function as second hash function hash(id) = last digit of id 2. Show the effect of deleting 000014 from the hash table
Suppose we have a hash map that uses the standard “mod” hash function shown in the chapter and uses linear probing for collision resolution. The starting hash table length is 5, and the table chooses to rehash to twice its former size once the load factor reaches or exceeds 0.5. If we begin with an empty map, what will be the final state of the hash table after the following key/value pairs are added and removed? Draw the entire array and the contents of each index, including any resizing and rehashing necessary. Write “X” in any index in which an element is removed and not replaced by another element. Also write the size, capacity, and load factor of the final hash table. HashMap<Integer, String> map = new HashMap<Integer, String>(); map.put(7, "Jessica"); map.put(34, "Tyler"); map.put(17, "Ryan"); map.put(15, "Tina"); map.put(84, "Saptarshi"); map.remove("Tyler"); map.put(7, "Meghan"); map.put(33, "Kona"); map.remove(17); map.put(6, "Tina"); map.remove(84); map.put(15,…
Hash table is a data structure in which keys are mapped to array positions by a hash function. Theprocess of mapping the keys to appropriate locations in a hash table is called hashing. Hash functions areused to reduce the number of collisions.i. Mention the methods to minimize collision.ii. Explain the advantage of using double hashing over linear and quadratic probing techniques.iii. Load the keys given below in a hash table of size 7 in the same order using chaining with thehash function h(key)= key % 7. Show graphically how collisions are resolved using chainingin this particular case.12, 101, 3, 21, 14, 13, 16, 7, 141
In Python, implement a hashing table data structure of size 20, which can cope with collisions. Thus, you must implement the closed collision system in its three modes: Linear scanQuadratic scanDouble hashing scan. For halt use halt(k)= (k mod (m - 1)) + 1, where m is the size of the table. The data to be managed are students from a certain university who have a 5-digit registration number and it is unique. In addition, the student has a name, age and address. Create a .txt file with 10 students (one for each line) and have them loaded into your program. Build a menu of options where you can: - Find a student and print his data if found and position in the table. Otherwise print a "Not Found" message.
In Python, implement a hashing table data structure of size 20, which can cope with collisions. Thus, you must implement the closed collision system in its three modes: Linear scanQuadratic scanDouble hashing scan. For halt use halt(k)= (k mod (m - 1)) + 1, where m is the size of the table. The data to be managed are students from a certain university who have a 5-digit registration number and it is unique. In addition, the student has a name, age and address. Create a .txt file with 10 students (one for each line) and have them loaded into your program. Build a menu of options where you can: - Enter a new student. For this option, that only allows entering the 5-digit license plate and that random data is automatically generated for the name, age and address. Return the position where it was entered and if it is not possible to enter it, print a message that explains why the entry was not obtained.
Consider an empty hash table of size 7. Draw the table that results after inserting, in the given order,the following key values: {19, 26, 13, 48, 17} when collisions are managed and handled by doublehashing method with function: ?(?,?) = [??(?) + ? ∗ ??(?)] ??? ?, where ℎ1(?) = ? ??? 7and ℎ2(?) = 5 − (? ??? 5).