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DIY: Merge K Sorted Lists

DIY: Group Anagrams

DIY: Find Median from a Data Stream

DIY: Validate Stack Sequences

DIY: Letter Combinations of a Phone Number

DIY: Sliding Window Median

DIY: Permutations

DIY: Maximum Frequency Stack

Facebook

22 Lessons

Go hands-on with enhancing Facebook-Instagram integration, content sharing, and coding challenges.

Project Description for Facebook

Feature #1: Friend Circles

Feature #2: Copy Connections

Feature #3: Find Story ID

Feature #4: Request Limiter

Feature #5: Flag Words

Feature #6: Combine Similar Messages

Feature #7: Divide Posts

Feature #8: Overlapping Topics

Feature #9: Recreating the Decision Tree

DIY: Number of Connected Components in an Undirected Graph

DIY: Number of Islands

DIY: Number of Provinces

DIY: Clone Directed Graph

DIY: Search in Rotated Sorted Array

DIY: Logger Rate Limiter

DIY: Expressive words

DIY: Group Shifted Strings

DIY: Divide Chocolate

DIY: Minimum Window Substring

DIY: Construct a Binary Tree from Preorder and Inorder Traversal

Search Engine

22 Lessons

Grasp the fundamentals of building an efficient search engine with key feature implementations.

Project Description for Search Engine

Feature #1: Store and Fetch Words

Feature #2: Design Search Autocomplete System

Feature #3: Add White Spaces to Create Words

Feature #4: Suggest Possible Queries After Adding White Spaces

Feature #5: Calculate the Search Ranking Factor

Feature #6: Reorganizing Search Results

Feature #7: Find Searching Time

Feature #8: Distributed Process Coordinator

Feature #9: Finding Minimum Servers

DIY: Suggest Relevant Sentences

DIY: Implement Trie

DIY: Word Break

DIY: Word Break II

DIY: Product of Array Elements Except Itself

DIY: Reorganizing a String

DIY: Exclusive Time of Functions

Google Calendar

17 Lessons

Take a closer look at solving scheduling and meeting management tasks using various algorithmic approaches.

Project Description for Google Calendar

Feature #1: Find Meeting Rooms

Feature #2: Show Busy Schedule

Feature #3: Check if Meeting is Possible

Feature #4: Schedule a New Meeting

Feature #5: Find Common Meeting Times

Feature #6: Find Two Sets of Consecutive Days

Feature #7: Longest Busy Period

DIY: Interval Lists Intersection

DIY: Find Interval Sets

DIY: Merge Intervals

DIY: My Calendar

DIY: Insert Interval

DIY: Employee Free Time

DIY: Find Two Non-Overlapping Subarrays Each with Target Sum

DIY: Longest Consecutive Sequence

Stock Scraper

13 Lessons

Tackle web scraping for stock data, DOM traversal techniques, and profit calculation strategies.

Project Description for Stock Scraper

Feature #1: Traversing DOM Tree

Feature #2: Locating Stock Data

Feature #3: Traversing DOM Tree II

Feature #4: Maximum Profit

DIY: Binary Tree Level Order Traversal

DIY: Lowest Common Ancestor of a Binary Tree

DIY: Lowest Common Ancestor of a Binary Tree III

DIY: Populating Next Right Pointers in Each Node

DIY: Populating Next Right Pointers in Each Node II

DIY: Maximum Subarray

DIY: Best Time to Buy and Sell Stock

UBER

18 Lessons

Build on optimizing Uber's driver allocation, path costs, fare conversion, and ride-sharing dynamics.

Project Description for Uber

Feature #1: Select Closest Drivers

Feature #2: Path Cost

Feature #3: Plot and Select Path

Feature #4: Fare in Words

Feature #5: Uber Pool

Feature #6: Longest Route

Feature #7: Highest Rank

Feature #8: Optimal Path

DIY: K Closest Points to Origin

DIY: Trapping Rainwater

DIY: Evaluate Division

DIY: Integer to English Words

DIY: Random Pick with Weight

DIY: Diameter of Binary Tree

DIY: Kth Largest Element in an Array

DIY: Minimum Path Sum

Amazon

34 Lessons

Sharpen your skills in solving complex coding challenges inspired by Amazon's innovative features.

Project Description for Amazon

Feature #1: Suggest Items for Free Delivery

Feature #2: Suggest Items for Special Offer

Feature #3: Upselling Products

Feature #4: Copy Product Data

Feature #5: Order Processing Milestones

Feature #6: Products Frequently Viewed Together

Feature #7: Optimize Delivery Cost

Feature #8: Merge Recommendations

Feature #9: Products in Price Range

Feature #10: Calculate the Total Cost of the Shopping Cart Items

Feature #11: Ad Serving

Feature #12: Warehouse and Drop Points

Feature #13: Time-Based Item Price Store

Feature #14: Find Similar Products

DIY: Insert, Delete, and GetRandom in O(1)

DIY: Insert Delete GetRandom O(1) - Duplicates Allowed

DIY: Copy List with Random Pointer

DIY: Find First and Last Position of an Element in Sorted Array

DIY: Find All Anagrams in a String

DIY: Random Pick Index

DIY: Continuous Subarray Sum

DIY: Accounts Merge

DIY: Range Sum of BST

DIY: Basic Calculator II

DIY: Basic Calculator III

DIY: Read N Characters Given Read4 II — Call Multiple Times

DIY: Walls and Gates

DIY: Time-Based Key-Value Store

DIY: Intersection of Two Arrays

Zoom

12 Lessons

Get started with implementing Zoom features, including participant management, serialization, mini-games, and mobile responsiveness.

Project Description for Zoom

Feature #1: Display Meeting Lobby

Feature #2: Serialize and Deserialize Participant Data

Feature #3: Meeting Activity

Feature #4: Validate Sorted Participants Data

Feature #5: Auto Rotate in Mobile Devices

DIY: Binary Search Tree Iterator

DIY: Serialize and Deserialize Binary Tree

DIY: Jump Game IV

DIY: Validate the Binary Search Tree

DIY: Rotate Image

10.

Plagiarism Checker

6 Lessons

Break apart the process of designing a plagiarism checker, identifying potential and matching subsequences.

Project Description for Plagiarism Checker

Feature #1: Possible Matches

Feature #2: Return Match

DIY: Number of Matching Subsequences

DIY: Minimum Window Subsequence

11.

Network

27 Lessons

Enhance your skills in implementing network functionalities through practical examples and coding challenges.

Project Description for Network

Feature #1: Total Time

Feature #2: TTL Expiry

Feature #3: Minimum Hops

Feature #4: Maximum Routers

Feature #5: Update VLAN ID

Feature #6: Transmission Error

Feature #7: Divide Files Over the Network

Feature #8: Maximum Clock Skew

Feature #9: Update Configuration

Feature #10: Minimum Variation

Feature #11: Weighted Exponential Back-off

Feature #12: Peak Signal Strength

DIY: Time Needed to Inform All Employees

DIY: All Nodes Distance K in Binary Tree

DIY: Jump Game II

DIY: Longest Increasing Path in a Matrix

DIY: Flood Fill

DIY: Valid Palindrome II

DIY: Partition Labels

DIY: Maximum Difference Between Node and Ancestor

DIY: Rotting Oranges

DIY: Longest Subarray With Absolute Diff Less Than Equal to Limit

DIY: Add Two Numbers

DIY: Add Two Numbers II

DIY: Find Peak Element

12.

Cyber Security

12 Lessons

Map out the steps for advanced encryption, packet validation, message integrity, and leader election optimization.

Project Description for Cyber Security

Feature #1: Validate Packet Structure

Feature #2: Verify Message Integrity

Feature #3: Find Dictionary

Feature #4: Ways to Decode Message

Feature #5: Eligible Candidates

DIY: Verifying an Alien Dictionary

DIY: UTF-8 Validation

DIY: Alien Dictionary

DIY: Decode Ways

DIY: Find K Closest Elements

13.

Operating System

35 Lessons

Focus on developing efficient OS features like memory, process management, and file systems with coding exercises.

Project Description for Operating System

Feature #1: Allocate Space

Feature #2: Resume Process

Feature #3: Schedule Processes

Feature #4: Compress File

Feature #5: Recover Files

Feature #6: File Management System

Feature #7: Serialize and Deserialize File System

Feature #8: Compress File II

Feature #9: File Search

Feature #10: Decode a Message

Feature #11: Directory Iterator

Feature #12: Priority Validation

Feature #13: Reverse Commands

Feature #14: Releasing Process Lock

Feature #15: Queue Reconstruction by Priority

DIY: Subarray Sum Equals K

DIY: Missing Element in a Sorted Array

DIY: Course Schedule

DIY: Course Schedule II

DIY: Sequence Reconstruction

DIY: Concatenated Words

DIY: Minimum Remove to Make Valid Parentheses

DIY: Design Add and Search Words Data Structure

DIY: Serialize and Deserialize N-ary Tree

DIY: String Compression

DIY: Regular Expression Matching

DIY: Wildcard Matching

DIY: 24 Game

DIY: Flatten Nested List Iterator

DIY: Frog Jump

DIY: Queue Reconstruction by Height

DIY: Reverse Words in a String

DIY: Single Element in a Sorted Array

14.

Language Compiler

22 Lessons

Master the steps to build an advanced C++ compiler with key optimization features and error handling.

Project Description for Language Compiler

Feature #1: Remove Comments

Feature #2: Evaluate the Arithmetic Expression

Feature #3: Loop Unrolling

Feature #4: Optimization by Replacement

Feature #5: Compilation Step Failure

Feature #6: Most Common Token

Feature #7: Exponentiation for Mobile Devices

Feature #8: Divide in Power Save Mode

Feature #9: Validate Program Brackets

DIY: Count a Word in the Comments

DIY: Basic Calculator

DIY: Decoding a String

DIY: Find and Replace in a String

DIY: First Bad Version

DIY: Nested List Weight Sum

DIY: Most Common Word

DIY: Pow(x, n)

DIY: Divide Two Integers

DIY: Valid Parentheses

DIY: Valid Parenthesis String

15.

Boggle

6 Lessons

Break down Boggle game mechanics, search algorithms, and gain problem-solving skills.

Project Description for Boggle

Feature #1: Search for a Single Word in the Boggle Grid

Feature #2: Search for Maximum Number of Words in the Boggle Grid

Project Description for Scrabble

DIY: Word Search I

DIY: Word Search II

16.

Scrabble 2.0

6 Lessons

Unpack the core of transforming Scrabble into a digital game with strategic word transformations.

Feature #1: Minimum Moves

Feature #2: Possible Results

Project Description for Game

DIY: Word Ladder I

DIY: Word Ladder II

17.

Game

9 Lessons

Work your way through coding solutions for game development problems like straights and max points.

Feature #1: Hand of Straights

Feature #2: Maximum Points You Can Obtain from Cards

Feature #3: Balloon Splash

DIY: Divide Array in Sets of K Consecutive Numbers

DIY: Find Maximum Sum from Either End of an Array

DIY: Remove All Adjacent Duplicates In String

DIY: Remove All Adjacent Duplicates in String II

18.

Stocks

19 Lessons

Apply your skills to implementing stock trading functions, enhancing performance, and tackling coding interview challenges.

Project Description for Stocks

Feature #1: Validate Price

Feature #2: Settling Period

Feature #3: Goals Fulfilled

Feature #4: Milestone Reached

Feature #5: Top Brokers

Feature #6: Assign Transactions

Feature #7: Process Transactions

Feature #8: Find Intervals

DIY: Split Array into Consecutive Subsequences

DIY: Valid Number

DIY: Task Scheduler

DIY: Searching a 2D Matrix

DIY: Top K Frequent Elements

DIY: Reverse Nodes in k-Group

DIY: Reverse Linked List II

DIY: String to Integer (atoi)

DIY: Daily Temperatures

19.

Computational Biology

21 Lessons

Dig into computational biology, DNA mutations, virus detection, protein identification, and gene analysis.

Project Description for Computational Biology

Feature #1: Mutate DNA

Feature #2: Detect Virus

Feature #3: Locate Protein

Feature #4: Identifying Proteins

Feature #5: Mutating a Virus

Feature #6: Identify a Species

Feature #7: Detecting a Protein

Feature #9: Kth Missing Gene

DIY: String Transforms into Another String

DIY: Longest Substring with At Most K Distinct Characters

DIY: Longest Palindromic Substring

DIY: Valid Palindrome

DIY: Next Permutation

DIY: Longest Substring without Repeating Characters

DIY: Palindrome Permutation

DIY: Palindromic Substrings

DIY: Edit Distance

DIY: Kth Missing Positive Number

20.

Cellular Operator(AT&T)

20 Lessons

Focus on optimizing cellular networks through coverage analysis, power management, and user data handling.

Project Description for Cellular Operator

Feature #1: Determine Location

Feature #2: Low Coverage Area

Feature #3: Power Up the Station

Feature #4: Query Peak Users

Feature #5: Densest Deployment

Feature #6: Maximum Users

Feature #7: Maximum Contiguous Area

Feature #8: Maximum Signal Strength

DIY: Search a 2D Matrix II

DIY: Largest Rectangle in Histogram

DIY: Maximal rectangle

DIY: Open Lock

DIY: Range Sum Query 2D — Immutable

DIY: Minimum Area Rectangle

DIY: Sliding Window Maximum

DIY: Max Area of an Island

DIY: Max Consecutive Ones III

DIY: Shortest Bridge

21.

Twitter

17 Lessons

Master Twitter feature APIs, manage tweets, analyze data, and tackle coding challenges.

Project Description for Twitter

Feature #1: Add Likes

Feature #2: Merge Tweets In Twitter Feed

Feature #3: Identify Peak Interaction Times

Feature #4: Split Users into Two Groups

Feature #5: Drawing a Global Profile of Viral Tweets

Feature #6: Incoming Tweets Predictor

Feature #7: Trending Hashtags

DIY: Maximum Sum of Three Non-Overlapping Arrays

DIY: Add Binary

DIY: Multiply Strings

DIY: Merge Sorted Arrays

DIY: Is Graph Bipartite?

DIY: The Skyline Problem

DIY: Moving Average from a Data Stream

DIY: Find Duplicate Files in System

22.

Trees

8 Lessons

Step through binary tree concepts from inversion and flipping to traversal, boundary, and flattening techniques.

Invert Binary Tree

Flip Equivalent Binary Trees

Binary Tree Maximum Path Sum

Binary Tree Zigzag Level Order Traversal

Binary Tree Right Side View

Binary Tree Vertical Order Traversal

Boundary of Binary Tree

Flatten Binary Tree to Linked List

23.

Miscellaneous

14 Lessons

Walk through practical solutions to varied algorithmic and data structure challenges.

Minimum Knight Moves

Sparse Matrix Multiplication

Design In-Memory File System

Reconstruct Itinerary

Text Justification

Gas Station

Strong Password Checker

Sudoku Solver

Pacific Atlantic Water Flow

Angle Between the Hands of a Clock

24.

Conclusion

1 Lessons

Explore further resources, focus on behavioral interviews, and strengthen coding skills effectively.

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