Hashing meaning in DSA

Hashing is defined as a data distribution technique that transforms given key into a different value using hash function for faster access to data.

Characteristics of Hashing:

• Hashing maps the data object to exactly one memory bucket.
• It allows uniform distribution of keys across the memory.
• Uses different functions to perform hashing such as mid square hash function, division hash, multiplication hash
• A hash function can be applied multiple times to get an empty Bucket.
• There are two types static hashing and dynamic hashing. Static uses a single function for hashing while in dynamic hashing the function changes from time to time.

Applications of Hashing:

• ISAM: IBM’s Indexed Sequential Access Method is an index based file access mechanism that uses hashing for the purpose of indexing files.
• Hashing is used in file systems for storing files in {key, value} form.
• Hashing is used in cybersecurity and information security for generating cryptographic information.
• Frequency Counting of elements.

Advantages of Hashing:

• It allows faster data access with the complexity of O(1).
• Allows data to be mapped faster by using keys.
• Increases performance by reducing insertion, and deletion time for data.

Disadvantages of Hashing:

• Bucket Overflow: If the bucket storing the data is out of space then it causes an error called bucket overflow.
• Skew: if a single bucket is selected for insertion more frequently then it is said to be skewed. This affects uniform and symmetrical distribution of data over buckets.

What else can you read?

• Introduction to Hashing – Data Structure and Algorithm Tutorials
• Introduction to Universal Hashing in Data Structure
• What is Hashing?