HashMaps

HashMaps?

• A HashMaps are a type of map.
• Maps are collections of key-value pairsthat are searchable.
• Maps are unordered.
• Maps store and retrieve data using the keys to identify entries.
• Keys must be unique. They cannot be changed(=immutable) e.g> <k:A, v:3> <k:A, v:4> CANNOT exist in the same map
• Values are not unique, and therefore, they can be changed(=mutable) e.g> <k:A, v:3> <k:B, v:3> CAN exist in the same map
• Maps also sometimes called dictionaries.
• A real life example of KVpairs is phone numbers and names.

Phone Number = KEY
Name = VALUE

Map ADT

Methods:

- V put(<K, V>)
- V get(K)
- V remove(K)
- int size()

• SIZE refers to the number of entries, n
• CAPACITY refers to the length of the backing array, N