README.md

Complete DSA Preparation Course

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Table of Contents

• Time Complexity
• Mathematics
• Bits Manipulation
• Recursion
• Arrays
• Searching
• Sorting
• Matrix
• Hashing
• String
• Linked List
• Stack
• Queue
• Tree
• Binary Search Tree
• Heap
• Graph
• Greedy
• Backtracking
• Dynamic Programming
• Trie

🟩 🟧 🟥

Mathematics

#	Title	Code	Document	Video	Difficulty	Tag
1	Absolute value		Theory		🟩 Easy	abs()
2	Celsius To Fahrenheit		Theory		🟩 Easy	Math
3	Roots of Quadratic equation		Theory		🟩 Easy	Math
4	Factorial Of Number				🟩 Easy	Math
5	Count digits in a factorial				🟩 Easy	Factorial, Math
6	Series GP				🟩 Easy	Basic Math
7	Prime Number				🟩 Easy	Basic Math
8	Exactly 3 Divisors		Theory		🟩 Easy	Basic Math
9	Addition Under Modulo		Theory		🟩 Easy	Modulo
10	Multiplication Under Modulo		Theory		🟩 Easy	Modulo
11	Modular Multiplicative Inverse				🟩 Easy	Modulo
12	Trailing zeroes in factorial				🟧 Medium	Logic
13	Prime Factors				🟧 Medium	Prime

Bits Manipulation

#	Title	Code	Document	Video	Difficulty	Tag
1	Find first set bit				🟩 Easy	Bits, Modulo
2	Rightmost different bit				🟩 Easy	XOR, Modulo
3	Check whether K-th bit is set or not				🟩 Easy	XOR, Modulo
4	Count total set bits				🟧 Medium	RIght shift
5	Bit Difference				🟩 Easy	Bits
6	Number is sparse or not				🟩 Easy	Bits
7	Longest Consecutive 1's				🟩 Easy	Bits
8	Gray Code				🟩 Easy	Xor, Right Shift
9	Gray to Binary equivalent				🟩 Easy	Xor, Right Shift
10	Power of 2				🟩 Easy	AND
11	Swap all odd and even bits				🟩 Easy	OR
12	Maximum AND Value				🟧 Medium	AND

Recursion

#	Title	Code	Document	Video	Difficulty	Tag
1	Print 1 to n without using loops				🟩 Easy	Recursion
2	Sum Of Digits				🟩 Easy	Recursion
3	Count Total Digits in a Number				🟩 Easy	Recursion
4	Digital Root				🟧 Medium	Recursion
5	Fibonacci Using Recursion				🟩 Easy	Recursion
6	Tower Of Hanoi				🟧 Medium	Recursion
7	Josephus problem				🟧 Medium	Recursion

Arrays

#	Title	Code	Document	Video	Difficulty	Tag
1

Searching

#	Title	Code	Document	Video	Difficulty	Tag
1

Sorting

#	Title	Code	Document	Video	Difficulty	Tag
1

Matrix

#	Title	Code	Document	Video	Difficulty	Tag
1	What is Multidimensional Arrays c++		Pdf	Video	🟩 Easy	Matrix, Array
2	Sum of upper and lower triangles		Pdf	Solution	🟩 Easy	Matrix, Array
3	Transpose of Matrix		Pdf	Solution	🟩 Easy	Matrix, Array
4	Rotate by 90 degree		Pdf	Solution	🟩 Easy	Matrix, Array
5	Multiply the matrices	c++	Pdf	Solution	🟩 Easy	Matrix, Array
6	Spirally traversing a matrix	c++	Pdf	Solution	🟧 Medium	Matrix, Array
7	Interchanging the rows of a Matrix	c++	Pdf	Solution	🟩 Easy	Matrix, Array
8	Matrix Interchange			Practice	🟩 Easy	Matrix, Array
9	Search in a row-column sorted Matrix	c++	Pdf	Solution	🟧 Medium	Matrix, Array
10	Boolean Matrix	c++	Pdf	Solution	🟧 Medium	Matrix, Array

Hashing

#	Title	Code	Document	Video	Difficulty	Tag
1	What is Hashing Data structure		Pdf	Theory	🟩 Easy	Hashing
2	Code of Hashing in c++	c++	Pdf	Solution	🟩 Easy	Hashing
3	Direct Access Table		Pdf	Theory	🟩 Easy	Hash
4	What is Hash Function and collision		Pdf	Theory	🟩 Easy	Hash
5	What is chaining in collision handling		Pdf	Theory	🟩 Easy	Hashing
6	What is unordered_set	c++	Pdf	Theory	🟩 Easy	Hash
7	What is unordered_map	c++	GFG	Theory	🟩 Easy	Hash
8	Non Repeating Element	c++	Pdf	Solution	🟩 Easy	Hashing
9	First Repeating Element	c++	Pdf	Solution	🟩 Easy	Hashing
10	Union of two arrays			Practice	🟩 Easy	Hashing
11	Intersection of Two Arrays	c++	Pdf	Solution	🟩 Easy	unordered_set
12	Key Pair	c++	Pdf	Solution	🟩 Easy	unordered_map
13	Subarray with sum 0	c++	Pdf	Solution	🟧 Medium	unordered_set
14	Winner of an election	c++	Pdf	Solution	🟩 Easy	unordered_map
15	Pairs with Positive Negative values	c++	Pdf	Solution	🟩 Easy	map, Vector
16	Print Anagrams Together / Group Anagrams	c++	Pdf	Solution	🟧 Medium	unordered_map, string
17	Relative Sort Array / Sort an array according to the other	c++	Pdf	Solution	🟧 Medium	Map
18	Custom Sort String	c++	Pdf	Solution	🟧 Medium	map
19	Sort Array by Increasing Frequency	c++	Pdf	Solution	🟩 Easy	map, Lambda
20	Longest Consecutive Sequence			Practice	🟧 Medium	map

String

#	Title	Code	Document	Video	Difficulty	Tag
1	Naive Pattern Search			Important	🟩 Easy	Pattern
2	Implement strStr()	c++	pdf		🟩 Easy	Pattern
3	Binary String				🟩 Easy	string
4	Anagram				🟩 Easy	string
5	Check if string is rotated by two places				🟩 Easy	string
6	Check if strings are rotations of each other or not				🟩 Easy	string
7	Isomorphic Strings				🟩 Easy	string
8	Check if a string is Isogram or not				🟩 Easy	string
9	Keypad typing				🟩 Easy	string
10	Repeated Character				🟩 Easy	string
11	Non Repeating Character	c++		solution	🟧 Medium	string
12	Maximum Occuring Character				🟩 Easy	string
13	Remove common characters and concatenate				🟩 Easy	string
14	Reverse words in a given string				🟩 Easy	string
15	Sum of numbers in string	c++	pdf	solution	🟧 Medium	string
16	Pangram Checking				🟩 Easy	string
17	Minimum indexed character				🟩 Easy	string
18	Smallest window in a string containing all the characters of another string				🟧 Medium	string
19	Nth number made of prime digits				🟩 Easy	Prime, string

Linked List

#	Title	Code	Document	Video	Difficulty	Tag
1	Introduction to Linked list Playlist c++			Theory	🟩 Easy	Linked List
2	Data structures Competitive Programming			Theory	🟩 Easy	DSA
3	Arrays in Data Structures			Theory	🟩 Easy	Arrays
4	Pointers in C++ with code Practice			Theory	🟩 Easy	Pointers
5	Struct in c++			Theory	🟩 Easy	Struct

Stack

#	Title	Code	Document	Video	Difficulty	Tag
1	What is stack		GFG Link	Solution	🟩 Easy	Stack, Array
2	Implement stack using array				🟩 Easy	Stack, Array
3	Implement Stack using Linked List				🟩 Easy	Stack, Linked List
4	Implement Stack using Linked List				🟩 Easy	Stack, Linked List
5	Remove All Adjacent Duplicates In String				🟩 Easy	Stack, string
6	Remove All Adjacent Duplicates in String II				🟧 Medium	Stack, string
7	Valid Parentheses				🟩 Easy	Stack, string
8	Implement two stacks in an array				🟩 Easy	Stack, Array
9	Valid Parentheses				🟩 Easy	Stack, string
10	Get min at pop				🟩 Easy	Stack, Array
11	Min Stack				🟩 Easy	Stack, Array
12	Delete middle element of a stack				🟩 Easy	Stack, STL
13	Infix to Postfix				🟩 Easy	Stack
14	Evaluate Reverse Polish Notation				🟧 Medium	Stack, Evaluation of Postfix Expression
15	Online Stock Span				🟧 Medium	Stack, Stock span problem
16	Next Greater Element II				🟧 Medium	Stack, Array
17	Largest Rectangle in Histogram				🟥 Hard	Stack, Array
18	The Celebrity Problem				🟧 Medium	Stack, Array

Queue

#	Title	Code	Document	Video	Difficulty	Tag
1	What is Queue		GFG Link	Solution	🟩 Easy	Queue, STL
2	Implement Queue using array				🟩 Easy	Queue, Array
3	Implement Queue using Linked List		Scaler Topics Link		🟩 Easy	Queue, Linked List
4	Queue Reversal				🟩 Easy	Queue, Stack
5	Queue using two Stacks				🟩 Easy	Queue, Stack
6	Implement Queue using Stacks				🟩 Easy	Stack, Queue
7	Stack using two queues				🟩 Easy	Stack, Queue
8	Generate Binary Numbers				🟩 Easy	Queue
9	Reverse First K elements of Queue				🟩 Easy	Queue, Stack
10	Circular tour				🟧 Medium	Queue, Sliding window

Tree

#	Question	Code	Document	Video	Difficulty	Tag
1	What is Tree		pdf	Solution1, solution2	🟩 Easy	Tree, Theory
2	What is Binary tree		pdf	solution	🟩 Easy	Tree, Binary Tree
3	How to code binary tree	c++		Solution	🟩 Easy	Tree, Code
4	Properties of Binary tree		pdf	solution	🟩 Easy	Tree, Node
5	Types of Binary tree		pdf	solution	🟩 Easy	Binary Tree
6	Tree Traversal		pdf	solution1, solution2	🟩 Easy	Traversal, Inorder
7	Code of Inorder Traversal	c++	pdf	solution	🟩 Easy	Inorder Traversal
8	Code of Preorder and Postorder	c++		Solution	🟩 Easy	Preorder, Postorder
9	Binary Tree Inorder Traversal	c++		Solution	🟩 Easy	Recursion, Tree
10	Binary Tree Preorder Traversal			Practice	🟩 Easy	Recursion, Tree
11	Binary Tree Postorder Traversal			Practice	🟩 Easy	Recursion, Tree
12	Same Tree	c++		Solution	🟩 Easy	Tree Traversal
13	Maximum Depth of Binary Tree	c++		Solution	🟧 Medium	Recursion, Tree
14	Children Sum Parent	c++		Solution	🟩 Easy	Recursion, Tree
15	Binary Tree Level Order Traversal	c++		Solution	🟧 Medium	Queue, Tree
16	Level order traversal Line by Line			Practice	🟩 Easy	stack, Tree
17	Binary Tree Zigzag Level Order Traversal	c++		Solution	🟧 Medium	Queue, Tree
18	Maximum Width of Tree				🟩 Easy	Tree
19	Balanced Binary Tree	c++		Solution	🟩 Easy	Tree
20	Left View of Binary Tree				🟩 Easy	Tree
21	Right View of Binary Tree				🟩 Easy	Tree
22	Lowest Common Ancestor in a Binary Tree				🟧 Medium	Tree
23	Diameter of Binary Tree				🟩 Easy	Tree
24	Vertical Width of a Binary Tree				🟩 Easy	Tree
25	Mirror Tree				🟩 Easy	Tree
26	Check if subtree				🟧 Medium	Tree
27	Make Binary Tree From Linked List				🟧 Medium	Tree

Binary Search Tree

#	Title	Code	Document	Video	Difficulty	Tag
1	Inorder traversal of a BST				🟩 Easy	BST, Tree
2	Search in a Binary Search Tree				🟩 Easy	BST, Tree

Heap

#	Title	Code	Document	Video	Difficulty	Tag
1	Heap sort			Solution	🟩 Easy	Heap Basic
2	Kth Largest Element in an Array			Solution	🟩 Easy	Heap Basic
3	Kth Largest Element in a Stream			Solution	🟩 Easy	Heap Basic
4	Top K Frequent Elements			Solution	🟩 Easy	Heap Basic
5	Minimum Cost of ropes			Solution	🟩 Easy	Heap Basic
6	Find K Closest Elements			Solution	🟧 Medium	Heap Medium
7	Merge k Sorted Arrays			Solution	🟧 Medium	Heap Medium
8	Find median in a stream			Solution	🟥 Hard	Heap Hard

Graph

#	Title	Code	Document	Video	Difficulty	Tag
1	Graph Introduction			Solution	🟩 Easy	Graph Theory
2	Adjacency Matrix in graph			Solution	🟩 Easy	Graph Basic
3	Adjacency List in graph			Solution	🟩 Easy	Graph
4	How to code graph			Solution	🟩 Easy	Graph
5	BFS Of Graph			Solution	🟩 Easy	Graph Theory
6	Find If Path Exists in Graph	C++		Solution	🟩 Easy	Graph BFS
7	Find the Town Judge	C++		Solution	🟩 Easy	Graph BFS
8	DFS Of Graph			Solution	🟩 Easy	Graph Theory
9	Number of Islands	C++		Solution	🟧 Medium	Graph DFS
10	Flood Fill	C++		Solution	🟩 Easy	Graph Theory
11	Detect cycle in undirected graph			Solution	🟩 Easy	Graph
12	Topological sort (Kahn's BFS)	C++	Pdf	Solution	🟩 Easy	Graph
13	Topological sort using DFS	C++	Pdf	Solution	🟧 Medium	Graph DFS
14	Detect Cycle in a Directed Graph	C++	Pdf	Solution	🟧 Medium	Graph GFG

Greedy

#	Title	Code	Document	Video	Difficulty	Tag
1

Backtracking

#	Title	Code	Document	Video	Difficulty	Tag
1

Dynamic Programming

#	Title	Code	Document	Video	Difficulty	Tag
1	Fibonacci Numbers - Top Down DP				🟩 Easy	Recursion

Trie

#	Title	Code	Document	Video	Difficulty	Tag
1	Insert and Search				🟧 Medium	Trie

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