Computing - Hash Tables

Hash tables and keys

What is the main advantage of a hash table?

You can quickly find items given a key.

A hash table is a type of what data type?

An Abstract Data Type.

How is an element’s key calculated?

Using a hash function.

A key-value hash table is sometimes called what?

A hash map.

What is a hashing algorithm?

A calculation applied to a key to transform it into an address.

What is it called when a hash function generates the same value for two different inputs?

A collision.

What is it called when you find a new place for a value after two inputs have the same hash?

Open addressing.

What is the formula for load factor?

\[\frac{\text{total items}}{\text{capacity}}\]

What can load factor be used for?

Calculating when it is necessary to allocate more space to store something.

Once a hash has been calculated, what operation is used to normalise it to the length of the array?

\[\text{mod}\]

What is a common method of calculating a hash for a string?

Adding together the ASCII numbers of the characters.