1.4.3 / 1.3.1 Hashing

What is hashing?

• A process of calculating a fixed length value from another value

• A method to retrieve original data from a fixed length value

• A way to store data in a database

• A technique to compress files

Which of the following is NOT a use of hashing?

• Generating disk addresses

• Storing and checking passwords

• Compressing video files

• Encrypting PIN numbers

Why is hashing considered a one-way process?

• Because it can be reversed easily

• Because you can’t get the original value back

• Because it is used for storing images

• Because it is a two-way process

In a hash table, why does its size often need to be smaller than the total number of possible inputs?

• To save memory

• To increase speed

• To reduce collisions

• To make it easier to manage

What is a collision in the context of hashing?

• When data is lost

• When data is duplicated

• When different data is mapped to the same index

• When data is encrypted

In a hash table, data is stored as a collection of what?

• Numbers

• Letters

• Key-value pairs

• Colors

What is the process of determining the position of data within an array called?

• Sorting

• Hashing

• Allocating

• Indexing

What is one of the main advantages of using hash tables?

• They are very slow.

• They enable very efficient searching.

• They are difficult to maintain.

• They require a lot of memory.

In the best case, how quickly can data be retrieved from a hash table?

• In linear time.

• In constant time.

• In exponential time.

• In quadratic time.

What operations are efficient in a hash table?

• Only adding data.

• Only deleting data.

• Adding, updating, and deleting data.

• Only updating data.