Hashing Techniques and Collision Resolution Methods in Data Structures

Resolving Collisions with Linked Lists

Colliding elements are stored in a linked list at the same address using pointers

Bucket Hashing

Data is placed into buckets based on certain characteristics instead of single slots

Digit Extraction

Selected digits from the key are extracted and combined to form the address

Subtraction Method

Subtracts a fixed memory location from the key to determine the address and is as limited as direct hashing

Modulo-Division

The address is key % list size and works with any list size but using a prime list size reduces collisions

Rotation Hashing

Rotates the last character of the key to the front often combined with other hashing methods and useful for serial keys

Folding Method (Shift)

The key is divided into equal-sized parts and these parts are added together to form the address

Mid-Square Hashing

The key is squared and the address is selected from the middle digits of the squared value

Direct Hashing

The key is used directly as the address with no algorithmic manipulation and requires an element for every possible key but has no collisions

Folding Method (Boundary)

The outer parts of the key are reversed before being added to the middle part

Pseudorandom Hashing

Uses the key as a seed in a pseudorandom number generator and scales the result using modulo division