Hash Tables and Collision Resolution

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Questions and Answers

What is one potential method to resolve collisions in a hash table?

Creating an overflow table (correct)

Using a larger hash function

Employing an alternate hash algorithm

Increasing the size of the original table

Which of the following describes an overflow table's operation?

All entries are placed in one location

Entries are sorted before insertion

Data is retrieved randomly

Data is searched sequentially (correct)

Which data structure can also be used to handle overflow in hash tables?

Binary tree

Stack

Array list

Linked list (correct)

What is the likelihood of collisions occurring in a hash table dependent on?

The hash function and data size Signup and view all the answers

What does the 'MOD' operation in hash functions typically determine?

The location in the hash table Signup and view all the answers

What is the primary reason for having a hash table larger than the exact number of data items?

To minimize the chance of collisions. Signup and view all the answers

What is the hash value calculated for the word 'Delaware' using the given method?

$805$ Signup and view all the answers

What is the result of $805 ext{ MOD } 10$ in the context of the hash function?

$5$ Signup and view all the answers

What occurs when two different items hash to the same index in a hash table?

A collision occurs. Signup and view all the answers

Which of the following statements about the hash function execution is NOT correct?

Hash functions always return a unique address. Signup and view all the answers

What does the hashing function do in relation to data organization?

Provides the start position for a linear search Signup and view all the answers

How is linear probing utilized in collision resolution with hash tables?

By occupying the next sequential address until finding an empty one Signup and view all the answers

What is the primary outcome of applying the hashing function to 'Delaware'?

Resolving to address 6 due to a collision with Florida Signup and view all the answers

What is indicated by the sum of ASCII values of the letters in the word 'Florida'?

It is used for computing the address in a hash table Signup and view all the answers

Why does the hash table use modulo operations in calculating addresses?

To constrain the addresses to fit within the table's capacity Signup and view all the answers

What is the primary purpose of a hash table?

To immediately find an item without comparing other items Signup and view all the answers

How does a hash table determine the position of an item?

By applying a hashing function to the item Signup and view all the answers

What data structure do programming languages commonly implement using hash tables?

Dictionaries Signup and view all the answers

Which of the following statements about hash tables is incorrect?

Hash tables require comparison of all items to find a specific item. Signup and view all the answers

What is the result of applying a hashing function to an initial piece of data?

A hash value representing its position Signup and view all the answers

What advantage do hash tables provide over traditional data structures?

Faster lookups without item comparison Signup and view all the answers

What would be a potential downside of using hash tables?

Difficulty in managing large collision occurrences Signup and view all the answers

Which component is essential for the functioning of a hash table?

A hashing function Signup and view all the answers

What is the primary goal of a good hashing function?

To result in as few collisions as possible Signup and view all the answers

Which method is mentioned as a simple solution for resolving collisions in hash tables?

Open addressing Signup and view all the answers

How should a good hashing function ideally behave in terms of computation speed?

It should be calculated quickly Signup and view all the answers

What characteristic should a good hashing function have regarding memory usage?

Use as little memory as possible Signup and view all the answers

What happens when two data items hash to the same position in a hash table?

A collision occurs Signup and view all the answers

Which data item is associated with Georgia when computed for a hash function?

Florida Signup and view all the answers

What is an essential property of a good hashing function regarding collisions?

Minimizing collisions improves efficiency Signup and view all the answers

If a hash function computes an address of 10 for 'California', what type of data structure does this imply?

A hash table Signup and view all the answers

Study Notes

Hash Tables

Hash tables provide a way to quickly find an item without needing to compare against other elements in a data set.
Hash tables are used to implement the dictionary data structure in programming languages.
A hashing function is used to calculate the position of an item in a hash table.
Hash tables must be large enough to hold all data items, but often larger to minimize the chance of collisions.
A collision occurs when the hashing function returns the same value for more than one item.
Good hashing functions are:
- Calculated quickly.
- Result in few collisions.
- Use little memory.

Collision Resolution

Strategies are used to resolve collisions.
Open addressing means repeatedly checking the next available space in the hash table until an empty position is found.
Linear probing finds the start position from which a linear search is applied until the item is found.
Another strategy is to use an overflow table for collisions, which can be searched sequentially.
A linked list can also be used to store collisions, searched sequentially.

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Description

This quiz covers the fundamentals of hash tables and the strategies for resolving collisions. Explore the principles of hash functions, the importance of minimizing collisions, and various collision resolution techniques. Test your knowledge on how hash tables enhance data retrieval efficiency in programming.