Consider a hash table of capacity 4 that uses open addressing with linear probing. This hash table uses a hash function that takes the remainder when the hash code of a string is divided by the capacity of the hash table. (For example, "air" hashes 0.) The hashCode method has been overridden for strings, which simply returns 0 if a string begins with 'a', 1 if it begins with 'b', etc. /** Returns 0 if a String begins with 'a', 1 if it begins with 'b', etc. */ public int hashCode() { return this.charAt(0) - 'a'; } Assume that "apple", and "cherry" have been inserted in this order into the hash table. "guava" is to be inserted into the hash table. (a) Which array slot/index should "guava" be placed? Answer: (b) What is the load factor after "guava" is inserted into the hash table? Answer:

Consider a hash table of capacity 4 that uses open addressing with linear probing. This hash table uses a hash function that takes the remainder when the hash code of a string is divided by the capacity of the hash table. (For example, "air" hashes 0.) The hashCode method has been overridden for strings, which simply returns 0 if a string begins with 'a', 1 if it begins with 'b', etc. /** Returns 0 if a String begins with 'a', 1 if it begins with 'b', etc. */ public int hashCode() { return this.charAt(0) - 'a'; } Assume that "apple", and "cherry" have been inserted in this order into the hash table. "guava" is to be inserted into the hash table. (a) Which array slot/index should "guava" be placed? Answer: (b) What is the load factor after "guava" is inserted into the hash table? Answer:

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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A message is made of 10 numbers between 00 and 99. A hash algorithm creates a digest out of this message by adding all numbers modulo 100. The resulting digest is a number between 00 and 99. Does this algorithm meet the first criterion of a hash algorithm? Does it meet the second criterion? Does it meet the third criterion?
Write a C++ program that: (1) defines and implements a hash class that constructs a 15 element array (may be implemented using a vector, a deque, or a list, if you prefer), storing strings, using the following hash function: ((first_letter) + (second_letter) + (last_letter))% 15 (2) the driver program should: a. query the user for ten words and store them using the hash technique described above. b. print out the contents of each position of the array (or vector, deque, or whatever you used), showing vacant as well as filled positions. Remember, only 10 of the 15 positions will be filled. c. repeatedly query the user for a target word, hash the word, check for its inclusion in the list of stored words, and report the result. Continue doing this task until the user signals to stop (establish a sentinel condition).
A hash code is generated by the Java hash function for Strings based on a string's highest allowed character count. Explain how a powerful, constant-time hashing algorithm can be created given that Strings have no useful maximum length. Which eight characters, say, would you select to represent a string of length l if you had to?
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Write a separate C function to implement the following hash functions with a formal parameter key. The function should return the hash value. Write a main program to generate keys randomly for around 100 keys and see how well your functions give unique hash values to each key. --Division Method with an integer key --Multiplication Method with an integer key and a value of (sqrt(5)-1)/2 for A --Mid-Square Method with 7-digit integer key --Folding Method with a 4-digit integer key
). This problem is about the chaining method we discussed in the class. Problem 3 (, Consider a hash table of size N = 11. Suppose that you insert the following sequence of keys to an initially empty hash table. Show, step by step, the content of the hash table. Sequence of keys to be inserted:
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Hashcode may implement from the Algorithm Robert Sedgwick book.