Data Structures

Types of Data Strucutres

Data Strucutres are divided into (2) categories

Linear Data Strcutres

Data Structures that store data in a sequential manner

Example: Array, Stack, Queue, Linked List, etc.



Non-Linear Data Structures

Data Structures that store data in a non-sequential manner

Example: Graphs, Trees.

Linear Data Strucutres

Array

Arrays are the most simplest type of Data Strucutre they are used to store similar Type of data and their memory allocation is sequential meaning they're stored one after the other and their memory is allocation is also done one after the other.

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Stack

Stack is a type of linear data structure and it works on the LIFO (Last in First out) principle

Basic operations of Stack are:

• Push():
adds an element on TOP of the stack
• pop():
removes an element from the TOP of the stack
• isEmpty():
checks wether the stack is empty
• peek():
used to display the element on top without removing it

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Queue

Queue - another example of Linear data struture. Queue is based on the FIFO (First in, First out) principle. Opposite to the Stack.

Basic operations of queue are:

• enqueue():
adds an element at the END of the queue
• dequeue():
removes an element at the FRONT of the queue
• peek():
displays the front-most element of the queue

Types of Queues

• Circular Queue:
in this type of queue the last element is connected to the first element of the queue.
• Deque:
Deque or Double Ended Queue is a type of queue in which insertion and removal of elements can either be performed from the front or the rear. Thus, it does not follow FIFO rule (First In First Out).
• Priority Queue:
A priority queue is a special type of queue in which each element is associated with a priority value. And, elements are served on the basis of their priority. That is, higher priority elements are served first.

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• Linked List

A linked list consists of NODES. Each node acts like a building block of linked list and each node consists of an ADDRESS & a VALUE. The first node known as the HEAD of linked list only contains an address and the last node of the linked list known as TAIL consist of a value and an address pointing NULL

Types of Linked Lists

• Singly Linked List:
each node only has (1) address and the direction of traversing can only be unidirectional.
• Doubly Linked List:
each node has (2) addresses & the direction of traversing can be bi-directional.

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Array List

Simply put, dynamic array. Where the size is initially fixed, but as the array grows and requires more space a new array is created double the size of original array and all the elements of the old array are copied into the new array