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Data Structures

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Introduction to Arrays

var vs. let vs. const

Challenge: Remove Even Integers From an Array

Solution Review: Remove Even Integers From an Array

Challenge: Merge Two Sorted Arrays

Solution Review: Merge Two Sorted Arrays

Challenge: Find Two Numbers that Add up to "value"

Solution Review: Find Two Numbers that Add up to "value"

Challenge: Array of Products of All Elements

Solution Review: Array of Products of All Elements

Challenge: Find Minimum Value in Array

Solution Review: Find Minimum Value in Array

Challenge: Find First Unique Integer in an Array

Solution Review: First First Unique Integer in an Array

Challenge: Find Second Maximum Value in an Array

Solution Review: Find Second Maximum Value in an Array

Challenge: Right Rotate an Array by n

Solution Review: Right Rotate an Array by n

Challenge: Rearrange Positive & Negative Values

Solution Review: Rearrange Positive & Negative Values

Challenge: Rearrange Sorted Array in Max/Min Form

Solution Review: Rearrange Sorted Array in Max/Min Form

Challenge: Maximum Sum Subarray

Solution Review: Maximum Sum Subarray

Arrays Quiz: Test Your Understanding of Arrays

Introduction to Linked Lists

Singly Linked Lists (SLL)Basic Linked List Operations Singly Linked List Insertion Challenge: Insertion at Tail Solution Review: Insertion at Tail Challenge: Search in a Singly Linked List Solution Review: Search in a Singly Linked List Singly Linked List Deletion Challenge: Deletion by Value Solution Review: Deletion by Value Deletion at the Tail Linked Lists vs. Arrays Challenge: Find the Length of a Linked List Solution Review: Find the Length of a Linked List Challenge: Remove Duplicates from Linked List Solution Review: Remove Duplicates from a Linked List Challenge: Union & Intersection of Linked Lists Solution Review: Union and Intersection of Linked Lists Challenge: Return the Nth Node from the End Solution Review: Return the Nth Node from the End Doubly Linked Lists (DLL)Singly Linked Lists vs. Doubly Linked Lists Linked Lists Quiz: Test Your Understanding of Linked Lists

Introduction to Stack/Queues

What is a Stack?Stack (Implementation)What is a Queue?Queue (Implementation)Challenge: Generate Binary Numbers From 1 to n Using Queue Solution Review: Generate Binary Numbers From 1 to n Using Queue Challenge: Implement Two Stacks using One Array Solution Review: Implementing Two Stacks Using One Array Challenge: Reversing First k Elements of Queue Solution Review: Reversing First k Elements of Queue Challenge: Implement a Queue Using Stacks Solution Review: Implement a Queue Using Stacks Challenge: Sort Values in a Stack Solution Review: Sort Values in Stack Challenge: Evaluate Postfix Expression Using a Stack Solution Review: Evaluate Postfix Expression Using a Stack Challenge: Next Greater Element Using a Stack Solution Review: Next Greater Element Using a Stack Challenge: Check Balanced Parentheses Using Stack Solution Review: Check Balanced Parentheses Using Stack Challenge: 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: Implement Breadth First Search Solution Review: Implement Breadth First Search Challenge: Implement Depth First Search Solution Review: Implement Depth First Search Challenge: Detect Cycle in Graph Solution Review: Detect Cycle in Graph Challenge: Find a "Mother Vertex" in a Graph Solution Review: Find a "Mother Vertex" in a Graph Challenge: Count the Number of Edges in an Undirected Graph Solution Review: Count the Number of Edges in an Undirected Graph Challenge: Check if a Path Exists Between Two Vertices Solution Review: Check if a Path Exists Between Two Vertices Challenge: Check if an Undirected Graph is Tree or not Solution Review: Check if an Undirected Graph is Tree or not Challenge: Find the Shortest Path Between Two Vertices Solution Review: Find the Shortest Path Between Two Vertices Challenge: Remove Edge Solution Review: Remove Edge Graph Quiz: Test Your Understanding of Graphs

Introduction to Trees

An Introduction to Trees and Basic Tree Properties!What is a Binary Tree?What Makes a Tree 'Balanced'?More on Complete Binary Trees Skewed Binary Tree What is a Binary Search Tree (BST)?Implementing a Binary Search Tree in JavaScript Binary Search Tree Insertion Binary Search Tree Insertion (Implementation)Pre-Order Traversal In-Order Traversal Post-Order Traversal Searching in a Binary Search Tree (Implementation)Deletion in Binary Search Tree Deletion in Binary Search Tree (Implementation)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: Find the Minimum Value in a Binary Search Tree Solution Review: Find the Minimum Value in Binary Search Tree Challenge: Find the kth Maximum Value in a Binary Search Tree Solution Review: Find kth Maximum Value in Binary Search Tree Challenge: Find Ancestors of a Given Node in a BST Solution Review: Find Ancestors of a Given Node in a BST Challenge: Find the Height of a BST Solution Review: Find the Height of a BST Challenge: 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 a Trie Challenge: Total Number of Words in a Trie Solution Review: Total Number of Words in a Trie Challenge: Find All Words Stored in Trie Solution Review: Find All Words Stored in Trie Challenge: Array Sort Using Tries Solution Review: Array Sort Using Tries Challenge: Word Formation from a Dictionary Using Trie Solution Review: Word Formation from a Dictionary Using a 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: Convert Max-Heap to Min-Heap Solution Review: Convert Max-Heap to Min-Heap Challenge: Find k Smallest Elements in an Array Solution Review: Find k Smallest Elements in an Array Challenge: Find k Largest Elements in an Array Solution Review: Find k Largest Elements in an Array 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 Tables Challenge: An Array as a Subset of Another Array Solution Review: An Array as a Subset of Another Array Challenge: Check if Arrays are Disjointed Solution Review: Check if Arrays are Disjointed Challenge: Find Symmetric Pairs in an Array Solution Review: Find Symmetric Pairs in an Array Challenge: Trace the Complete Path of a Journey Solution Review: Trace the Complete Path of a Journey Challenge: Find Two Pairs in an Array Such That a+b = c+d Solution Review: Find Two Pairs Such That a+b = c+d Challenge: A Subarray with a Sum of 0 Solution Review: A Subarray with a Sum of 0 Challenge: Find Two Numbers that Add up to "value"Solution Review: Find Two Numbers that Add up to "value"Challenge: Find First Unique Integer in an Array Solution Review: Find First Unique Integer in an Array Challenge: Remove Duplicates from a Linked List Solution Review: Remove Duplicates from a Linked List Challenge: Union of Linked Lists Solution Review: Union & Intersection of Linked Lists Hashing Quiz: Test Your Understanding of Hashing

Conclusion

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Challenge: Find First Unique Integer in an Array

Challenge: Find First Unique Integer in an Array

Try to solve the First NonRepeating Integer in an Array problem.

Statement

Given an array nums, find the first nonrepeating integer in it.

Constraints:

$1 \leq$ ...