🧠 JS Data Structures & Algorithms

Welcome to the JS Data Structures & Algorithms repository!
This project takes you from JavaScript basics all the way to advanced DSA problems, making it a perfect companion for interviews, competitive programming, and system design preparation.

📌 Repository: js-data-structures-algorithms
👨‍💻 Author: ExploitEngineer

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📁 Topics Covered

1️⃣ Basic JavaScript Logic

• Sum of two numbers
• Type coercion & string concatenation
• Swap variables (3 methods)
• Operators: Arithmetic, Relational, Logical, Unary
• Math Functions: round(), ceil(), floor(), trunc(), pow(), sqrt(), abs(), random(), toFixed()
• Problems:
  • Rectangle area & perimeter
  • OTP generator
  • Triangle area (Heron’s formula)
  • Circle circumference

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2️⃣ Conditional Statements & Control Flow

• If-Else, Ternary, Switch
• Problems:
  • Valid user checker
  • Shop discount logic
  • Utility bill (Biji bill)
  • INR denomination

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3️⃣ Loops

• For, While, Do-While
• Problems:
  • Print "Hello" N times
  • 1 to N and N to 1
  • Sum & factorial
  • Prime number
  • Sum of digits
  • Strong number
  • Reverse number
  • Guess the number
  • Calculator app

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4️⃣ Pattern Programming

• Nested loops
• Classic pattern problems

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5️⃣ Arrays

• Fixed vs Dynamic arrays
• Accept user input
• Problems:
  • Sum of elements
  • Max & second max
  • Reverse array
  • Shift zeros left, ones right

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6️⃣ Strings

• String methods
• Problems:
  • Character-by-character printing
  • Reverse string
  • Palindrome checker
  • Toggle case
  • Character frequency

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7️⃣ Object-Oriented Programming

• Class & Object
• Constructor, this, Prototype
• Design-based problems

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🔥 The Real DSA Journey Begins Here

8️⃣ Advanced Array Questions

• Left/Right rotation by K
• Remove duplicates (sorted array)
• Merge sorted arrays
• Best time to buy & sell stock
• Sort colors
• Kadane’s Algorithm
• Moore’s Voting
• Trapping Rain Water

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9️⃣ Sorting Algorithms (Part 1)

• Bubble Sort
• Selection Sort
• Insertion Sort

🔟 Sorting Algorithms (Part 2)

• Merge Sort
• Quick Sort

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1️⃣1️⃣ Cyclic Sort

• Missing number
• Disappeared numbers
• First missing positive

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📌 Binary Search

• Classic Binary Search
• Search Insert Position
• Rotated Sorted Array
• Book Allocation
• Koko Eating Bananas
• Threshold limit problems

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🧠 Hashing

• Frequency map
• Unique elements
• Pangram checker
• Sort by people
• Two Sum
• Subarray sum equals K
• Longest subarray with sum K
• Longest consecutive sequence

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🔗 Linked List

• Implementation
• Design LL
• Find middle
• Detect cycle
• Reverse list
• Delete node
• Reverse in K groups

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📚 Stack & Queue

• Stack & Queue implementation
• Valid parentheses
• Stack using queue
• Queue using stack
• Next greater element
• Largest rectangle in histogram

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🔁 Recursion & Backtracking

• Print Hello N times
• N to 1, 1 to N
• Sum & factorial
• Digit sum
• Fibonacci (2 ways)
• Tower of Hanoi
• Josephus problem
• Subsets & permutations
• Combination sum
• Sudoku solver

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🌳 Binary Tree

• Implementation
• DFS (Pre, In, Post)
• Max depth
• Symmetric tree
• BFS
• Left & Top view
• Lowest Common Ancestor
• Build tree (Preorder + Inorder)

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🌲 Binary Search Tree

• Validate BST
• Kth smallest in BST
• Delete node from BST

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🌐 Graph

• Graph implementation
• BFS & DFS
• Cycle detection
• Topological sort
• Shortest Path Algorithms

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⚙️ Tech Stack

• Language: JavaScript (ES6+)
• Tools: Git, GitHub, Notion (for notes)
• Practice Style: Problem-first, then explanation

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🛠️ Setup

# Clone this repo
git clone https://github.com/ExploitEngineer/js-data-structures-algorithms.git

# Move into project folder
cd js-data-structures-algorithms

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🙌 Contribute If you find bugs or want to improve the code/docs:

• Star ⭐ this repo
• Fork 🍴 the project
• Open a PR or Issue

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📄 License MIT License — feel free to use, modify, or share!

Happy coding, keep learning, and never stop solving! 🚀✨