Practice machine coding of top low level design (LLD) interview questions using design patterns

Id	Title	Companies	Design Pattern	Difficulty
7.	Design a Parking Lot	Amazon LLD Microsoft Goldman Sachs	Strategy	Medium
6.	Design a Hit Counter/Webpage Visits Counter - Multi-Threaded	Amazon LLD Adobe Atlassian		Medium
5.	Design a restaurant food ordering system like Zomato, Swiggy, DoorDash	Uber Flipkart ClearTax	Observer	Medium
14.	Design Unix "find" command for file search	Amazon LLD	Strategy	Medium
15.	Design Unix "find" command - with boolean predicates	Amazon LLD	Specification	Hard
8.	Design Chess Game	Microsoft Salesforce Adobe	Factory	Medium
18.	Design Pizza Pricing System	Amazon LLD	Decorator	Medium
19.	Design Pizza Pricing System - Followup	Amazon LLD	Decorator	Medium
12.	Design expense sharing app like Splitwise	Salesforce Quince Flipkart		Medium
9.	Design a Text Editor/Word Processor like Microsoft Word	Microsoft Qualcomm	Flyweight	Medium
25.	Design spreadsheet like Microsoft Excel	Microsoft	Flyweight	Medium
20.	Design Stock Trading Platform Like Zerodha, Groww	Amazon LLD		Medium
11.	Design a Simple Elevator System - Multiple Lifts	Microsoft Adobe Oracle	State	Hard
10.	Design a Movie ticket booking system like BookMyShow	Salesforce Microsoft Uber	Observer	Medium
16.	Design Locker Management System for Warehouse Packages	Amazon LLD		Medium
21.	Design a Car Rental System	Amazon LLD Uber Flipkart		Medium
22.	Design a Job Scheduler	Microsoft Salesforce		Medium
23.	Design an Elevator System - Request Feasibility (Single Lift)	Microsoft		Medium
24.	Design Elevator Management System - Single Lift	Microsoft Adobe Oracle	State	Medium
26.	Design Dictionary App to store words and their meanings	Microsoft Google		Medium
27.	Design a Text Editor with Undo & Redo	Microsoft Google Amazon LLD	Command	Hard
28.	Design a Container Orchestrator System	Microsoft	Strategy	Medium
4.	Design an order and inventory management system - Multi-Threaded	WayFair Intuit Tiktok		Medium
3.	Design a customer issue resolution system - Multi-Threaded	PhonePe Atlassian	Strategy	Hard
1.	Design a Parking Lot - Multi-Threaded	Amazon LLD Microsoft Goldman Sachs		Medium
29.	Design a Meeting room reservation System	Uber		Medium
30.	Design a File System (cd with '*')	Uber Atlassian		Medium
31.	Design a Leaderboard for Fantasy Teams	Uber Microsoft WayFair	Observer	Medium
32.	Design a Train Platform Management System	Uber		Medium
33.	Design a Single-Queue Publish Subscribe System	Uber InMobi PayPal	Observer	Medium
34.	Design a rate limiter	Atlassian Microsoft Oracle		Medium
35.	Design a customer support agent rating leaderboard	Atlassian	Observer	Medium
36.	Design a Middleware Router	Atlassian		Medium
37.	Design a File Collections Tracker	Atlassian	Strategy	Medium
38.	Design a Product Plan Cost Explorer	Atlassian		Medium
39.	Design a Text Editor with cursor operations and Basic Editing	PayPal		Medium
40.	Design a Text Editor with cursor operations	PayPal		Medium
41.	Design a Shopping Cart	PayPal Amazon LLD Walmart		Medium
42.	Design a Payment Wallet like PayPal	PayPal Flipkart Razorpay		Medium
43.	Design a Custom HashMap	PayPal Walmart Flipkart		Medium
44.	Design a Meeting Room Scheduler - List Bookings	Salesforce Uber		Medium
45.	Design a Meeting Room Scheduler for Recurrent Meetings	Salesforce Uber		Medium
46.	Design Last Lap Hero (F1 Race Tracker)	Atlassian	Observer	Medium
47.	Design a RPC Framework	Salesforce		Medium
48.	Design an In-Memory Cache with Custom Eviction Policy	Salesforce	Strategy	Medium
49.	Design a Connection Pool with an Internal Request Queue	Salesforce Walmart		Medium
72.	Design a Kafka like Message Streaming Service with Multiple Topics	Flipkart ClearTrip Uber		Medium
73.	Design a Billing and discounts System for an ecommerce app	Flipkart ClearTrip		Medium
74.	Design Food Order Management System using Commands	Flipkart ClearTrip		Medium
75.	Design Gym Fitness Center Management and Slot Booking System	Flipkart ClearTrip		Medium
76.	Design Peer to Peer Parcel Delivery System	Flipkart ClearTrip		Medium
77.	Design Flipkart Payment Wallet with Transaction History	Flipkart ClearTrip		Medium
78.	Design Doctor Appointment Booking app like Practo	Flipkart ClearTrip		Medium
79.	Design a Bug Bounty Program Management System	Flipkart ClearTrip		Medium
80.	Design Flipkart Buy Now Pay Later	Flipkart ClearTrip		Medium
81.	Design a Library Management System	Flipkart ClearTrip Amazon LLD		Medium
82.	Design Customer Loyalty Program for Ecommerce Website	Flipkart ClearTrip Amazon LLD		Medium
83.	Design Flipkart Delivery Service	Flipkart ClearTrip		Medium
84.	Design Dating App Gumble	Flipkart ClearTrip		Medium
85.	Design Social Network News Feed	Flipkart ClearTrip		Medium
86.	Design Stock Market Investing Platform	Flipkart Goldman Sachs ClearTrip		Medium
87.	Design Time Versioned Key Value Store	OpenAI		Medium
88.	Design Resumable Iterator for Large Dataset	OpenAI		Medium
89.	Design GPU Credit Calculator	OpenAI		Medium
90.	Design Database with SQL Commands	OpenAI		Medium
91.	Design File Downloader Library	OpenAI		Medium
92.	Design Type System for a Toy Programming language	OpenAI		Medium
93.	Design Live News Feed System	Walmart Flipkart	Observer	Medium
94.	Design Order Notification System	Walmart	Observer	Medium
95.	Design System for Managing Workflows	Walmart		Medium
96.	Design Warehouse Stores Inventory Updater System	Walmart	Observer	Easy
97.	Design Dasher Payout Service	DoorDash		Medium
98.	Design Workflow Automation Engine for Self Help Menu	DoorDash		Medium
99.	Find Longest Sequence of Pickup Jobs for Dashers	DoorDash		Medium
100.	Find Closest DashMart Distance and DashMart Serving Maximum Customers	DoorDash		Medium
101.	Maximum Calories within Budget	DoorDash		Medium
102.	Aggregate Gift Card Data	DoorDash		Medium
103.	Dasher Payout Logic - Simple	DoorDash		Medium
104.	Chef Order Preparation List	DoorDash		Medium
105.	Count and Print Changed Nodes in DoorDash Menu Tree	DoorDash		Medium
106.	Longest Path and Increasing Paths in a Grid	DoorDash Google Meta		Medium
107.	DoorDash Restaurant Search Engine	DoorDash		Medium
108.	Matrix Special Elements	Goldman Sachs		Medium
109.	String Burst	Goldman Sachs		Medium
110.	Highest Average Student Score	Goldman Sachs		Easy
111.	Maximum Stones Path Sum	Goldman Sachs Amazon DS & Algo		Medium
112.	Largest Tree in a Forest	Goldman Sachs		Medium
113.	Minimum Cost Array	Goldman Sachs		Medium
114.	Hospital Triage Priority Scheduling	Goldman Sachs		Medium
115.	Eliminate Substring	Goldman Sachs		Medium
116.	Bitwise XOR Subsequences	Goldman Sachs		Medium
117.	Single Element in Sorted Array - Pairs, Triplets	Goldman Sachs		Medium
118.	Virus Spread in Directed Graph	Goldman Sachs		Medium
119.	Top K Tallest Buildings	Goldman Sachs		Medium
120.	Count Prefix Using Trie	Goldman Sachs		Medium
121.	Top K Frequent Numbers in a Stream	Goldman Sachs		Medium
122.	First Non Repeated Character in a Stream	Goldman Sachs		Medium
123.	Minimum Characters to Remove from Ends to Make a Palindrome	Goldman Sachs		Medium
124.	Container With Most Water Upright and Tilted	Goldman Sachs		Medium
125.	Design a Traffic Signal Light System	Goldman Sachs		Medium
126.	Design Parking Lot Pricing System	Goldman Sachs		Medium
127.	Combine Integer Arrays / Lists	Goldman Sachs		Medium
128.	Max Path Sum in Matrix	Goldman Sachs		Medium
129.	Currency Conversion	Goldman Sachs		Medium
130.	Design Snake and Ladder Game	Goldman Sachs Amazon LLD Microsoft		Medium
131.	Count Number of Unconnected Trees in a Forest	Goldman Sachs		Medium
132.	Design a TTL (Time to Live) Cache	Goldman Sachs		Medium
133.	Design Notification System	Goldman Sachs Eightfold AI	Observer	Medium
134.	Design Order Checkout and Payment for E-commerce Website	Goldman Sachs		Medium
135.	Design URL Shortener	Goldman Sachs		Medium
136.	Compress String using Prefix Pattern	Goldman Sachs		Medium
137.	Count String Prefixes on Tree Paths	Google		Hard
138.	Detect First Timed Out Job from Logs	Google		Medium
139.	Count Visible People in Queue with Taller Observer Rule	Google		Hard
140.	Maximum Sum Subarray with Equal First and Last Elements	Google		Medium
141.	Longest Constrained Path in Matrix	Google		Hard
142.	Repeated Characters in Dictionary Words Due To Faulty Keyboard	Google		Medium
143.	Detect Squares Rotated along the XY Plane	Google		Hard
144.	Sum of All Good Arithmetic Sequences	Google		Medium
145.	Compile Packages with Dependencies in a Multi-Threaded Environment	Google		Medium
146.	Equal Sum Subsets with K Changes	Google		Medium
147.	Undirected Graph Path Queries	Google		Medium
148.	Array Range Update Queries	Google		Medium
149.	Router Reachability on Broadcast and Shutdown Message	Google		Medium
150.	First Bad Product Version	Google		Medium
151.	Design Logger Message Printer	Google		Medium
152.	Longest Path in Grid	Google		Medium
153.	Merge Working Hour Intervals Timeline	Google		Medium
154.	Days When Everyone is Free	Google		Medium
155.	Size of Unpainted Segments	Google		Medium
156.	Overall Distance Error Between Checkpoints and Samples	Google		Medium
157.	Minimum CPUs Needed for Earliest Tasks Completion	Google		Medium
158.	Total Scores of Leaf Domains	Google		Medium
159.	Place Nth Rook	Google		Medium
160.	Find Most Active Users in Chat Logs	Google		Medium
161.	Design BookShelf Manager with Bookmark Functionality	Google		Medium
162.	Run Length Encoding for List of Characters	Google		Medium
163.	Router Broadcast and Shutdown Message With Collisions	Google		Medium
164.	Max Words Visible on Scrollable Screen	Amazon DS & Algo		Medium
165.	Design LRU Cache With Time Constraint	Google		Medium
166.	Assign Aggressive Cows To Stalls	Amazon DS & Algo		Medium
167.	Trim Tree To Complete Binary Tree	Amazon DS & Algo		Medium
168.	Design WhatsApp Read Receipts	Amazon LLD		Medium
169.	Two Sum Closest To And Less Than Target	Amazon DS & Algo		Medium
170.	Search Minimum And Rotation Count In Rotated Sorted Array	Amazon DS & Algo		Medium
171.	Use Path Operations To Minimize Tree Diameter	Amazon DS & Algo		Medium
172.	Design Backup System for a File Storage Service	Amazon LLD		Medium
173.	Maximum Power Assigned To Machines	Amazon DS & Algo		Medium
174.	Minimum Cost to Join Sticks	Amazon DS & Algo		Medium
175.	Longest Subarray Sum Equals Zero	Amazon DS & Algo		Medium
176.	Find Kth Largest Element From Chef's Collection	Amazon DS & Algo		Medium
177.	Fill Grid Based on Crop Frequency	Amazon DS & Algo		Medium
178.	Design Digital Wellbeing System to Track App Screen Usage	Amazon LLD		Medium
179.	Minimum Meeting Rooms Required	Amazon DS & Algo		Medium
180.	Passenger Count During Car Trips	Amazon DS & Algo		Medium
181.	Design Vending Machine Leasing System	Amazon LLD		Medium
182.	Alien Language Letter Order	Amazon DS & Algo		Medium
183.	Design Google Like Search Autocomplete System	Amazon DS & Algo Google Microsoft		Medium
184.	Count Connected Groups in Undirected Graph	Amazon DS & Algo		Medium
185.	Verify Undirected Graph Valid Tree	Amazon DS & Algo		Medium
186.	Design Stack With Peek And Pop Maximum Element	Amazon DS & Algo Google		Medium
187.	Design Logger System With Message Timestamps	Amazon DS & Algo Google		Medium
188.	Employee Schedule Common Free Time	Amazon DS & Algo Google		Hard
189.	Find Missing Numbers In Range	Amazon DS & Algo		Medium
190.	Count Distinct Islands In Grid	Amazon DS & Algo Google		Medium
191.	Calculator To Evaluate Simple Expression String	Amazon DS & Algo Google		Hard
192.	Design Tic Tac Toe Game	Google Amazon DS & Algo Apple		Medium
193.	Insert Into Circular Linked List While Keeping It Sorted	Amazon DS & Algo		Medium
194.	Use Robot To Clean Every Reachable Empty Cell In Room	Amazon DS & Algo		Medium
195.	Multiply Sparse Matrices	Amazon DS & Algo Google		Medium
196.	Longest Substring With At Most Two Distinct Characters	Amazon DS & Algo		Medium
197.	Longest Substring With At Most N Distinct Characters	Amazon DS & Algo Google		Hard
198.	Find Anagram Index Mapping	Amazon DS & Algo		Medium
199.	Design System To Store Logs With Timestamp	Amazon DS & Algo Google X (Twitter)		Medium
200.	Maximum Enemies Killed By One Bomb	Amazon DS & Algo		Medium
201.	Next Larger Palindrome Using Same Digits	Amazon DS & Algo		Medium
202.	Design Snake Game With Food And Score	Amazon DS & Algo Google Meta		Medium
203.	Generate Palindromic Permutations Of String	Amazon DS & Algo Google		Medium
204.	Shortest Word Distance Between Words	Amazon DS & Algo		Medium
205.	Find Celebrity At Party	Amazon DS & Algo		Medium
11166.	Design File System	Amazon LLD Airbnb		Medium
10588.	Design In-Memory File System	Amazon LLD Airbnb		Hard
10379.	Design Phone Directory	Google Microsoft		Medium
10631.	Design Excel Sum Formula	Amazon LLD Microsoft		Hard
10362.	Design Hit Counter	Google Amazon LLD Adobe		Medium

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Prashant Priyadarshi
Founder, CodeZym