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Data Structures

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Introduction to Lists

Lists Arrays Lists vs Arrays in Python Challenge 1: Remove Even Integers from List Solution Review: Remove Even Integers from a List Challenge 2: Merge Two Sorted Lists Solution Review: Merge Two Sorted Lists Challenge 3: Find Two Numbers that Add up to "k"Solution Review: Find Two Numbers that Add up to "k"Challenge 4: List of Products of all Elements Solution Review: List of Products of All Elements Challenge 5: Find Minimum Value in List Solution Review: Find Minimum Value in List Challenge 6: First Non-Repeating Integer in a list Solution Review: First Non-Repeating Integer in a list Challenge 7: Find Second Maximum Value in a List Solution Review: Find Second Maximum Value in a List Challenge 8: Right Rotate List Solution Review: Right Rotate List Challenge 9: Rearrange Positive & Negative Values Solution Review: Rearrange Positive & Negative Values Challenge 10: Rearrange Sorted List in Max/Min Form Solution Review: Rearrange Sorted List in Max/Min Form Challenge 11: Maximum Sum Sublist Solution Review: Maximum Sum Sublist Lists Quiz: Test your understanding of Lists

Introduction to Linked List

Singly Linked Lists (SLL)Linked Lists vs. Lists Basic Linked List Operations Singly Linked List Insertion Challenge 1: Insertion at Tail Solution Review: Insertion at Tail Challenge 2: Search in a Singly Linked List Solution Review: Search in a Singly Linked List Singly Linked List Deletion Challenge 3: Deletion by Value Solution Review: Deletion by Value Doubly Linked Lists (DLL)Singly Linked Lists vs. Doubly Linked Lists Challenge 4: Find the Length of a Linked List Solution Review: Find the Length of a Linked List Challenge 7: Find Middle Node of Linked List Solution Review: Find Middle Node of a Linked List Challenge 8: Remove Duplicates from Linked List Solution Review: Remove Duplicates from a Linked List Challenge 9: Union & Intersection of Linked Lists Solution Review: Union & Intersection of Linked Lists Challenge 10: Return the Nth node from End Solution Review: Return the Nth Node from End Linked Lists Quiz: Test your understanding of Linked Lists

Introduction to Stacks and Queues

What is a Stack?Stack (Implementation)What is a Queue?Queue (Implementation)Challenge 1: Generate Binary Numbers from 1 to n using a Queue Solution Review: Generate Binary Numbers from 1 to n using Queue Challenge 2: Implement Two Stacks Using One List Solution Review: Implementing Two Stacks Using One List Challenge 3: Reversing First k Elements of Queue Solution Review: Reversing First k Elements of Queue Challenge 4: Implement a Queue Using Stacks Solution Review: Implement a Queue Using Stacks Challenge 5: Sort Values in a Stack Solution Review: Sort Values in Stack Challenge 6: Evaluate Postfix Expression Using a Stack Solution Review: Evaluate Postfix Expression Using a Stack Challenge 7: Next Greater Element Using a Stack Solution Review: Next Greater Element Using a Stack Challenge 8: Check Balanced Parentheses Using Stack Solution Review: Check Balanced Parentheses using Stack Challenge 9: min( ) Function Using a Stack Solution Review: min( ) Function Using a Stack Stack/Queue Quiz: Test your understanding of Stack/Queue

Introduction to Graphs

What is a Graph?

Types of Graphs

Representation of Graphs

Graph Implementation

Complexities of Graph Operations

What is a Bipartite Graph?

Graph Traversal Algorithms

Challenge 1: Implement Breadth First Search

Solution Review: Implement Breadth First Search

Challenge 2: Implement Depth First Search

Solution Review: Implement Depth First Search

Challenge 3: Detect Cycle in a Directed Graph

Solution Review: Detect Cycle in a Directed Graph

Challenge 4: Find a "Mother Vertex" in a Directed Graph

Solution Review: Find a "Mother Vertex" in a Directed Graph

Challenge 5: Count Number of Edges in an Undirected Graph

Solution Review: Count the Number of Edges in an Undirected Graph

Challenge 6: Check if a Path Exists Between Two Vertices

Solution Review: Check if a Path Exists Between Two Vertices

Challenge 7: Check if a Given Undirected Graph is Tree or not?

Solution Review: Check if Given Undirected Graph is a Tree or Not

Challenge 8: Find the Shortest Path Between Two Vertices

Solution Review: Find the Shortest Path Between Two Vertices

Challenge 9: Remove Edge

Solution Review: Remove Edge

Graph Quiz: Test your understanding of Graphs

Introduction to Trees

Trees and their Basic Properties!What makes a tree 'balanced'?What is a Binary Tree?More on Complete Binary Trees Skewed Binary Trees What is a Binary Search Tree (BST)?Implementing a Binary Search Tree in Python Binary Search Tree Insertion Binary Search Tree Insertion (Implementation)Searching in a Binary Search Tree (Implementation)Deletion in a Binary Search Tree Deletion in a Binary Search Tree (Implementation)Pre-Order Traversal Post-Order Traversal In-Order Traversal What is an AVL Tree?AVL Insertion AVL Deletion What is a Red-Black Tree?Red-Black Tree Insertion Red-Black Tree Deletion What is a 2-3 Tree?2-3 Insertion 2-3 Deletion (Case #1)2-3 Deletion (Case #2)2-3-4 Trees Overview of Trees Challenge 1: Find minimum value in Binary Search Tree Solution: Find minimum value in Binary Search Tree Challenge 2: Find kth maximum value in Binary Search Tree Solution Review: Find kth maximum value in Binary Search Tree Challenge 3: Find Ancestors of a given node in a BST Solution Review: Find Ancestors of a given node in a BST Challenge 4: Find the Height of a BST Solution Review: Find the Height of a BST Challenge 5: Find Nodes at "k" distance from the Root Solution Review: Find Nodes at "k" distance from the Root Trees Quiz: Test your understanding of Trees

Trie

What is a Trie?Structure of a Trie Insertion in a Trie Search in a Trie Deletion in Trie Challenge 1: Total Number of Words in a Trie Solution Review: Total Number of Words in a Trie Challenge 2: Find All Words Stored in Trie Solution Review: Find All Words Stored in Trie Challenge 3: List Sort Using Trie Solution Review: List Sort Using Trie Challenge 4: Word Formation From a Dictionary Using Trie Solution Review: Word Formation From a Dictionary Using Trie Trie Quiz: Test Your Understanding of Tries

Introduction to Heap

What is a Heap?Max Heap: Introduction Max Heap (Implementation)Min Heap: Introduction Min Heap (Implementation)Challenge 1: Convert Max-Heap to Min-Heap Solution Review: Convert Max-Heap to Min-Heap Challenge 2: Find k smallest elements in a List Solution Review: Find k smallest elements in a List Challenge 3: Find k largest elements in the List Solution Review: Find k Largest Elements in the List Heap Quiz: Test your understanding of Heaps

Introduction to Hashing

What is a Hash Table?The Hash Function Collisions in Hash Tables Building a Hash Table from Scratch Add/Remove & Search in Hash Table (Implementation)A Quick Overview of Hash Tables Trees vs Hash Table Dictionary vs Set Challenge 1: A List as a Subset of Another List Solution Review: A List as a Subset of Another List Challenge 2: Check if Lists are Disjoint Solution Review: Check if Lists are Disjoint Challenge 3: Find Symmetric Pairs in a List Solution Review: Find Symmetric Pairs in a List Challenge 4: Trace the Complete Path of a Journey Solution Review: Trace the Complete Path of a Journey Challenge 5: Find Two Pairs in List such that a+b = c+d Solution Review: Find Two Pairs Such That a+b = c+d Challenge 6: A Sublist with a Sum of 0 Solution Review: A Sublist with a Sum of 0 Challenge 7: Word Formation Using a Hash Table Solution Review: Word Formation Using a Hash Table Challenge 8: Find Two Numbers that Add up to "k"Solution Review: Find Two Numbers that Add up to "k"Challenge 9: First Non-Repeating Integer in a List Solution Review: First Non-Repeating Integer in a list Challenge 10: Detect Loop in a Linked List Solution Review: Detect Loop in a Linked List Challenge 11: Remove Duplicates from Linked List Solution Review: Remove Duplicates from Linked List Challenge 12: Union & Intersection of Linked Lists Solution Review: Union & Intersection of Linked Lists Hashing Quiz: Test your understanding of Hashing

Conclusion

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Solution Review: Implement Depth First Search

Solution Review: Implement Depth First Search

Let’s solve the Implement Depth-First Search problem.

Statement

Given a directed graph represented by an adjacency list graph and an integer source, representing the start vertex of the graph, return a list of integers, result that shows the order of depth-first traversal starting from the specified source vertex.

Constraints

$1$ $\leq$ graph.length $\leq$ $10^3$
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