Sigma 8.0 (DSA with C++)

Placements & Internships

About the Lectures

Pre-requisites

What to Install?

For Mac Users - Setting up C++

Using VS Code

Components of Flowchart

Sum of 2 Numbers

Calculate Simple Interest

Max of 2 Numbers

Print N Natural Numbers

Sum of N Natural Numbers

How does code run?

Preprocessor Directive

Main Function in C++

What is Namespace?

Output in C++

Print the Pattern

Variables in C++

Naming Conventions

Identify Valid Names

Data Types in C++

Comments

Input in C++

Print Average Marks

Implicit Type Conversion

Explicit Typecasting

Practice Qs

Arithmetic Operators

Unary Arithmetic Operators

Assignment Operators

Relational Operators

Logical Operators

Practice Qs

Else if Statements

Practice Qs

Practice Qs

Ternary Operator

Switch Statement

Build a Calculator

Print "apna college"

Print N Natural Numbers

Sum of N Natural Numbers

while Loop

Practice Qs

Practice Qs

do while Loop

break Statement

Practice Qs (break)

continue Statement

Practice Qs (continue)

Check for Prime

Check for Prime (Optimized)

Nested Loops (Dry Run)

Star Pattern

Inverted Star Pattern

Half Pyramid Pattern

Character Pyramid Pattern

Hollow Rectangle Pattern

Inverted & Rotated Half-Pyramid Pattern

Floyd's Triangle Pattern

Diamond Pattern

Butterfly Pattern

Forward Declaration

Syntax with Parameters

Practice Qs

Practice Qs (Factorial)

Function call in Memory

Scope (Local & Global)

Practice Qs (Prime Number)

Practice Qs (Binomial Coefficient)

Function Overloading

Practice Qs (Primes in Range)

Convert Binary to Decimal

Convert Decimal to Binary

Question (Decimal to Binary)

Common Numbers in Binary

Data Type Modifiers

Binary to Decimal (Code)

Decimal to Binary (Code)

AddressOf (&) Operator

What are Pointers?

Dereference Operator

Null Pointers

Passing Arguments (Value vs Reference)

Reference Variables

Practice Qs

Practice Qs

Creating an Array

Output & Input Array

Find Largest in Array

Arrays are passed by Reference

Linear Search

Reverse an Array

Binary Search

Binary Search Code

Binary Search (Time Complexity)

Array Pointer

Pointer Arithmetic 1

Pointer Arithmetic 2

Pointer Arithmetic 3

Pointer Arithmetic 4

Max Sum Subarray (Brute Force)

Max Sum Subarray (Slightly Optimized)

Kadane's Algorithm for Max Sum Subarray

Buy & Sell Stocks

Buy & Sell Stocks (Code)

Trapping Rainwater

Trapping Rainwater (Code)

Bubble Sort (Code)

Selection Sort

Selection Sort (Code)

Insertion Sort

Insertion Sort (Code)

Counting Sort

Counting Sort (Code)

In-built Sort in C++

Practice Qs

Input & Output a 2D Array

2D Arrays in Memory

Spiral Matrix

Spiral Matrix (Code)

Diagonal Sum

Diagonal Sum (Code)

Search in Sorted Matrix

Search in Sorted Matrix (Code)

Matrix Pointers

Matrix Pointers in Functions

Character Array

Input Char Array

Convert to UpperCase

Reverse a Char Array

Valid Palindrome

cstring Functions

OOPs Intro (for Strings)

C++ Strings

for each Loop

String Member Functions

Valid Anagram

Valid Anagram (Code)

Dynamic Memory Allocation

Static v/s Dynamic Allocation

Memory Leak

2D Dynamic Arrays

What is STL?

Vector Introduction

Vector Implementation in Memory

Pair Sum

2D Vectors

Practice Qs

One's Complement

Bitwise Shift Operators

Practice Qs

Check if Odd or Even

Get ith Bit

Set ith Bit

Clear ith Bit

Check for Power of 2

Update ith Bit

Clear Last i Bits

Count Set Bits

Fast Exponentiation

Fast Exponentiation (Code)

Access Modifiers

Getters & Setters

Encapsulation

Constructor

Practice Qs

Copy Constructor

Shallow & Deep Copy

Destructor

Inheritance

Mode of Inheritance

Single Inheritance

Multi-level Inheritance

Multiple Inheritance

Hierarchical & Hybrid Inheritance

Function Overloading

Operator Overloading

Function Overriding

Virtual Functions

Abstraction

Pure Virtual Function

Static Keyword

Static Objects

Friend Functions & Class

Practice Qs

Practice Qs

Dive Deep into Recursion

Recursion in Memory

Numbers in Decreasing Order

Dry Run with Call Stack

Stack Overflow

Sum of N Natural Numbers

Nth Fibonacci

Nth Fibonacci (Code)

Check if Array Sorted

First Occurrence

Last Occurrence

Print X to the power N

X to the power N (Code)

Tiling Problem (Code)

Remove Duplicates in String

Remove Duplicates (Code)

Friends Pairing Problem

Friends Pairing (Code)

Binary Strings Problem

Binary Strings (Code)

Binary Strings (Dry Run)

Merge / Combine Step

Merge Sort (Code)

Merge Sort (Summary)

Quick Sort Algorithm

Quick Sort (Code)

Worst Case Time Complexity - Quick Sort

Search in Rotated Sorted Array

Rotated Sorted (Pseudocode)

Rotated Sorted (Code)

What is Time Complexity?

Constant Time Complexity

Big O Notation

Big O from Functions

Big O Math Formula (Optional)

Other Notations

What is Space Complexity?

Common Time Complexities

Constant & Linear TC

Quadratic TC

Practice Qs 1

Practice Qs 2

Practice Qs 3

Bubble Sort Analysis

Logarithmic TC (Binary Search Analysis)

O(n) vs O(logn) - Linear vs Log

Recursive Sum of N Numbers

Recursive Factorial of N

Recursive Nth Fibonacci

Merge Sort Analysis

Power Function Analysis

Practice Qs

How to approach Coding Qs?

Backtracking on Arrays

Find Subsets

Find Subsets (Code)

Find Permutations

Find Permutations (Code)

N Queens Qs Discussion

N Queens (Approach)

isSafe in N Queens (Approach)

N Queens (Time Complexity)

N Queens Variations

Grid Ways

Grid Ways (Code)

Grid Ways (Dry Run)

Grid Ways (Time Complexity)

Grid Ways (Optimization)

Sudoku Solver

Sudoku Solver (Code)

isSafe in Sudoku Solver

LL Implementation

Push Front in LL

Push Back in LL

Print LL

Insert in Middle of a LL

Deleting the Linked List

Pop Front in LL

Pop Back in LL

Iterative Search in LL

Recursive Search in LL

Reverse a Linked List

Find & Remove Nth Node from End

Find & Remove Nth (Code)

Detect a Cycle (Code)

Removing Cycle in LL

Removing Cycle (Code)

Removing Cycle (Math Proof)

List in STL

Merge Sort on a LL

Merge Sort (Split At Mid)

Merging 2 Sorted Lists

Zig Zag Linked List

Zig Zag LL (Alternate Merging)

Doubly Linked List (Push Front)

Doubly Linked List (Pop Front)

Stack using Vector

Stack using Vector & Class Template

Stack using LinkedList

Stack in STL

Push at Bottom of Stack

Push at Bottom (Code)

Reverse a String using Stack

Reverse a Stack

Stock Span

Stock Span (Approach)

Stock Span (Code)

Next Greater Element (Code)

Valid Parentheses

Valid Parentheses (Code)

Duplicate Parentheses

Duplicate Parentheses (Code)

Max Area in Histogram

Max Area in Histogram (nextSmaller Logic)

Max Area in Histogram (Code)

Implementation using LinkedList

Circular Queue using Array

Queue in STL

Queue using 2 Stacks

Stack using 2 Queues

First non-repeating letter

First non-repeating letter (Code)

Interleave 2 Queues

Interleave 2 Queues (Code)

Queue Reversal

Double Ended Queue

Queue using Deque

Stack using Deque

Activity Selection Problem

Activity Selection (Approach)

Activity Selection (Code)

Activity Selection (Proof)

Pairs in C++

Fractional Knapsack

Fractional Knapsack (Code)

Min Absolute Difference of Pairs

Max Chain Length

Max Chain Length (Code)

Indian Coins

Indian Coins (Code)

Job Sequencing Problem

Job Sequencing Variation

Levels & Subtrees

Practice Quiz

Build Tree from Preorder

Preorder Traversal

Inorder Traversal

Postorder Traversal

Level Order Traversal

Height of Binary Tree

Height of BT (Code)

Count of Nodes in BT

Sum of Nodes in BT

Diameter of a Tree ( Code )

Diameter of a Tree ( Approach 2 )

Diameter of a Tree ( Code 2 )

Subtree of another Tree

Subtree of another Tree (isIdentical)

Map in C++

Top View of a Tree (Horizontal Distance)

Top View of a Tree ( Approach )

Top View of a Tree ( Code )

Lowest Common Ancestor

Lowest Common Ancestor (Code)

LCA (Approach 2)

LCA (Approach 2) Code

Min Distance between Nodes

Kth Ancestor of a Node

Kth Ancestor (Code)

Transform to Sum Tree

Search in BST

Insert & Build a BST

Search in BST (Code)

Delete a Node in BST

Inorder Successor

Delete a Node (Code)

Print in Range

Root to Leaf Path

Validate BST

Validate BST (Code)

Sorted Array to Balanced BST (Code)

BST to Balanced BST

BST to Balanced BST (Code)

Largest BST in BT

Largest BST in BT (Code)

Merge 2 BSTs

PQ in C++ STL

What are Heaps?

Building Heaps

Push in Heap

Push in Heap (Code)

Pop in Heap

Pop in Heap (Code)

Pop in Heap (Dry Run)

PQ for Objects

PQ for Pairs

Heap Sort (Sorting)

Nearby Cars

Nearby Cars (Code)

Connect N Ropes

Connect N Ropes (Code)

Weakest Soldier

Weakest Soldier (Code)

Sliding Window Maximum

Sliding Window Maximum (Code)

Hash Table Data Structure

Hashing (Hash Function)

Collisions

Building Hash Table

Insert in Hash Table

Rehashing

Search in Hash Table

STL Containers

Unordered Maps

Maps

Unordered Sets

Sets

Majority Element (Code)

Valid Anagram

Valid Anagram (Code)

Count Distinct

Union & Intersection

Itinerary from Tickets

Itinerary from Tickets (Code)

Zero Sum Largest Subarray

Zero Sum Largest Subarray (Code)

K Sum Subarray Count

K Sum Subarray Count (Code)

Search in Trie

Building a Trie DS

Insert in Trie

Search in Trie

Word Break Problem

Word Break (Code)

Prefix Problem

Prefix (Code)

StartsWith Problem

Count Unique Substrings

Count Unique Substrings (Code)

Longest Word with all Prefix

Longest Word (Code)

Types of Graphs

Graph using Adjacency List

Graph using Adjacency Matrix

Edge List & Implicit Graph

Building a Graph (Adjacency List)

Breadth First Traversal (BFS)

BFS Code

Depth First Traversal (DFS)

DFS Code

Has Path Problem

Cycle in Graphs

Cycle Detection (Undirected)

Cycle Detection Code (Undirected)

Undirected approach for Directed

Cycle Detection (Directed)

Cycle Detection Code (Directed)

Cycle Detection Dry Run (Directed)

Bipartite Graph

Bipartite Graph (Code)

Bipartite Graph (Approach 2)

All Paths Problem

Topological Sorting (DFS)

Topological Sorting Code (DFS)

Course Schedule I

Course Schedule II

Kahn's Algorithm (Indegree)

Topoplogical Sorting (Kahn's Algorithm)

Kahn's Algorithm Code

Kahn's Algo for Cycle Detection

Dijkstra's Algorithm (Approach)

Dijkstra's Algorithm (Code)

BellmanFord Algorithm (Approach)

BellmanFord Algorithm (Code)

What is MST?

Prim's Algorithm

Prim's Algorithm (Code)

Min Cost to Connect Points

Cheapest Flights (Code)

Disjoint Set (Union Find)

Disjoint Set (Code)

Kruskal's Algorithm

Kruskal's Algorithm (Code)

Flood Fill Algorithm

Flood Fill (Code)

DP using Fibonacci Concept

What is DP?

Fibonacci using Tabulation

Types of DP

Important DP Concepts

Climbing Stairs (Recursion)

Climbing Stairs (Memoization)

Climbing Stairs (Tabulation)

Variation of Climbing Stairs

0-1 Knapsack

0-1 Knapsack (Recursion Code)

0-1 Knapsack (Memoization)

0-1 Knapsack (Tabulation)

Target Sum Subset

Unbounded Knapsack