DSA-library

Introduction

I would be learning data structures and algorithm properly and extensively in 2023(over its span).
During this learning spree:

• Python programming language would be used as the major tool of implementation.
• Each concept would be documented properly in here.

Data Structures

Linked list

An alternative to arrays(better off at times)

Features:

• Insertion
  • Insert at the beginning
  • Insert at the end
  • Insert at index
  • Insert multiple values
• Deletion
  • Delete by value
  • Delete by index
• Existence -> bool
• Get Existence index -> int
• Length
• Count of value
• Print linked list

Doubly Linked list

Double linked list

Features:

• Insertion
  • Insert at the beginning
  • Insert at the end
  • Insert at index
  • Insert multiple values
• Deletion
  • Delete by value
  • Delete by index
• Existence -> bool
• Get Existence index -> int
• Length(optimised O(1))
• Count of value
• Print linked list forward and backward

HashMap or HashTable

For storing key-value pair using a hash function

Features:

• Insert key value pair
• Retrieve value of key
• Hash function
• Ensure uniqueness of key
• Resetting value of a key
• check if key exists in hash table

Stack

Implemented using deque(double ended queue) in python. stack operates on the Last in First Out (LIFO) mode

Features:

• get length
• add to stack
• pop last item from stack
• return last item without popping(peek)
• check if empty
• print stack

Queue

Implemented using deque(double ended queue) in python. Queue operates on the First in First Out (FIFO) mode

Features:

• get length
• add to queue(enqueue)
• pop first item from stack
• return first item without popping(peek)
• check if empty
• print queue

Tree

A non-linear data structure, see it as your normal tree with root, branches and leaves.

Features:

• get level of a tree node
• print tree in designated format
• add children(leaves) to a treenode(branch)

Binary Tree

A non-linear data structure, a special kind of tree in which a treenode(branch) can have a maximum of two chidren(leaves) in which the lesser data always falls to the left of the treenode and the greater data falls to the right of the treenode.

Features:

• insertion operation
• deletion operation (ask me about this)
• sum of data in tree
• get minimum and maximum data in tree
• check existence of a data in the tree
• Print tree
  • in order traversal
  • pre order traversal
  • post order traversal

Algorithms

Search

Linear search

Search for a number in an array, sorted or unsorted and returns the index, iterates all through to where the number exists

Time complexity

O(n)

Binary search

Search for a number in a sorted array, and returns the index, divides the array in halves until number is found where existing.

Time complexity

O(log n)

Learning Source

Code basics

• Youtube
• Github