{"id":19924,"date":"2026-03-13T10:15:24","date_gmt":"2026-03-13T04:45:24","guid":{"rendered":"https:\/\/www.placementpreparation.io\/blog\/?p=19924"},"modified":"2026-04-07T16:51:21","modified_gmt":"2026-04-07T11:21:21","slug":"hashing-algorithm-in-data-structure","status":"publish","type":"post","link":"https:\/\/www.placementpreparation.io\/blog\/hashing-algorithm-in-data-structure\/","title":{"rendered":"Hashing Algorithm in Data Structure"},"content":{"rendered":"

How do login systems verify usernames and passwords instantly? How do databases retrieve specific records without scanning millions of entries? How do modern applications avoid slow linear searches when handling large datasets?<\/p>

The answer lies in hashing, a technique that enables fast data retrieval by mapping keys directly to storage locations using hash functions. Instead of searching through all data, hashing allows systems to access information almost instantly.<\/p>

In this article, you will learn what hashing is, how hash tables work, how collisions are handled, the time complexity of hashing operations, and how hashing is implemented in real programs.<\/p>

What is Hashing in Data Structures?<\/h2>

Hashing is a technique used in data structures to map keys to specific positions in a table using a hash function, allowing fast data storage and retrieval.<\/p>

Instead of searching through all elements, hashing directly calculates the storage location, making operations much faster.<\/p>

Simple flow:<\/strong><\/p>

\n

Key → Hash Function → Index → Hash Table<\/p>\n<\/div><\/div>

Example:<\/strong><\/p>

\n

Student ID → apply hash function → get index → store student record<\/p>\n

For example, if the student ID is 123 and the hash function is ID % 10, the index becomes 3, and the data is stored at position 3.<\/p>\n<\/div><\/div>

Components of Hashing<\/h2>

Hashing works through several important components that together enable fast data storage and retrieval. Understanding these components helps in clearly understanding how hash tables function.<\/p>\n\n\n\n\n\n\n\n\n
Component<\/b><\/td>\nMeaning<\/b><\/td>\n<\/tr><\/thead>
Key<\/span><\/td>\nInput value used to generate an index<\/span><\/td>\n<\/tr>\n
Hash Function<\/span><\/td>\nConverts key into an index value<\/span><\/td>\n<\/tr>\n
Hash Table<\/span><\/td>\nData structure that stores values<\/span><\/td>\n<\/tr>\n
Bucket<\/span><\/td>\nMemory location where data is stored<\/span><\/td>\n<\/tr>\n
Collision<\/span><\/td>\nSituation when multiple keys map to same index<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>

\"components<\/h2>

What is a Hash Function?<\/h2>

A hash function is a function that takes a key as input and converts it into an index position in a hash table. This index determines where the data will be stored or retrieved from.<\/p>

A good hash function should have the following properties:<\/strong><\/p>