Mega Post— Tech Interview : The Only List of Questions You Need To Practice

Mega Compilation — Use it just as a reference/practice resource…

Burn Freddy Burn (Pic credits : Pinterest)

Welcome back peeps. I’m creating this post to help students/anyone who wants to get into tech — who are preparing for their tech interviews. While I’m sitting on the other side of the table as an interviewer now; I know how daunting the prep journey can be. Use it just as a reference/practice resource and you may bookmark this list.

Advanced SQL Series

Day 1 : SQL Basics and Kick start of Advanced SQL Series

Day 2 : SQL Basics, Query Structure, Built In functions Conditions

Day 3 : Most Important Commands, Joins and Filters

Day 4 : Set Theory Operations, Stored Procedures and CASE statements in SQL

Day 5 : Wildcards, Aggregation and Sequences in SQL

Day 6 : Subqueries, Group by, order by and Having clauses in SQL and Analytical Functions

Day 7 : Window Functions, Grouping Sets and Constraints in SQL

Day 8 : BigQuery Basics, SELECT, FROM, WHERE and Date and Extract in BigQuery

Day 9 : Common Expression Table, UNNEST Clause, SQL vs NoSQL Databases

Day 10 : Triggers, Pivot and Cursors in SQL

Day 11 : Views, Indexes and Auto Increment in SQL

Day 12 : Query optimizations, Performance tuning in SQL

Day 13 : Introduction to MySQL, PostgreSQL and Mongo DB, Comparison between MySQL and PostgreSQL and Mongo DB, Introduction to SQL and NoSQL Databases

Day 14 : MySQL in Depth

Day 15 : PostgreSQL inDepth

System Design Case Studies — In Depth

Design Instagram

Design Netflix

Design Reddit

Design Amazon

Design Messenger App

Design Twitter

Design URL Shortener

Design Dropbox

Design Youtube

Design API Rate Limiter

Design Web Crawler

Design Amazon Prime Video

Design Facebook’s Newsfeed

Design Yelp

Design Uber

Design Tinder

Design Tiktok

Design Whatsapp

Mega Compilation : Solved System Design Case studies

Complete Data Structures and Algorithm Series

Complexity Analysis

Sliding Window

Backtracking

Greedy Technique

Two pointer Technique

1- D Dynamic Programming

Divide and Conquer Technique

Recursion

Github —

GitHub — Coder-World04/Complete-Data-Structures-and-Algorithms: This repository contains everything…

This repository contains everything you need to become proficient in Data Structures and Algorithms Start here : Day 1…

github.com

Some of the other best Series —

30 Days of Natural Language Processing ( NLP) Series

How to solve any System Design Question ( approach that you can take)?

Complete System Design Case Studies Series

30 days of Data Structures and Algorithms and System Design Simplified

60 Days of Deep Learning with Projects Series

60 days of Data Science and ML Series with projects

Data Science and Machine Learning Research ( papers) Simplified **

60 Days of Deep Learning with Projects Series

100 days : Your Data Science and Machine Learning Degree Series with projects

23 Data Science Techniques You Should Know

Tech Interview Series — Curated List of coding questions

Complete System Design with most popular Questions Series

Complete Data Visualization and Pre-processing Series with projects

Complete Python Series with Projects

Complete Advanced Python Series with Projects

Kaggle Best Notebooks that will teach you the most

Complete Developers Guide to Git

All the Data Science and Machine Learning Resources

210 Machine Learning Projects

30 days of Machine Learning Ops

Projects Videos —

Subscribe today!

Ignito

Excited to share that we have launched our Youtube channel — Ignito to cover all the projects and coding exercise for …

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Tech Newsletter —

If you are interested, you can join my newsletter through which I send tech interview tips, techniques, patterns, hacks — Software Development, ML, Data Science, Startups and Technology projects to more than 30K readers. You can subscribe to Tech Brew :

Ignito

Data Science, ML, AI and more… Click to read Ignito, by Naina Chaturvedi, a Substack publication with hundreds of…

naina0405.substack.com

This post is divided into —

Most important/most frequently asked topic wise list
Company wise list
Curated List ( post)
System Design list

Disclaimer : This list consists of those questions ( some of my favorite questions I ask while interviewing candidates) which gives you a very good understanding of data structures, algorithms, system design and a good grip on problem solving. This post no way endorses that you should practice only these questions; instead you must do these questions along with other questions of your choice during your preparations. good luck in advance.

Whenever I get time next weekend, I’ll write another post covering some tips, patterns and techniques to solve coding questions and how to write optimized code fast.

Highly Recommended Data Science and Machine Learning Courses that you MUST take ( with certificate) —

Complete Data Scientist

Complete Data Analyst

Complete Data Engineering

Complete Machine Learning Engineer

Complete Deep Learning

Complete Natural Language Processing

Complete Self Driving Car Engineer

Find best data science and data engineering courses here

Find best Machine Learning and Deep Learning courses here

Useful Tip — Some topics like DP, Tree, Graphs, Binary Search, Linked List are more important than other remaining topics from preparation pov.

Lets’ dive in!

Dynamic Programming

Analyzing Video using Python, OpenCV and NumPy

Analyzing Video using Python, OpenCV and NumPy

With Code Implementation…

medium.datadriveninvestor.com

For complete 60 days of Data Science and ML : Day 1 — Day 60 : Quick Recap of 60 days of Data Science and ML

Day 1 — Day 60 : Quick Recap of 60 days of Data Science and ML

Connect the ML dots…

medium.com

Clustering Geolocation Data in Python using DBSCAN and K-Means

Clustering Geolocation Data in Python using DBSCAN and K-Means

Project Implementation…

medium.datadriveninvestor.com

Hyperparameter Tuning with Keras Tuner

Hyperparameter Tuning with Keras Tuner

Project Implementation….

medium.datadriveninvestor.com

Part 1 of Data Science and ML mega series ( Day 0 — Day 20) can be found here —

Data Science And Machine Learning Projects — Mega Compilation Part 3

Part 1…

medium.com

Python Iterators, Generators And Decorators Made Easy

Python Iterators, Generators And Decorators Made Easy

A Quick Implementation Guide

python.plainenglish.io

Maths for Data Science and Machine learning

Day 8–60 days of Data Science and Machine Learning

Maths Part 2..

medium.datadriveninvestor.com

Recursion/Backtracking

100 days : Your Data Science and ML Degree

100 days : Your Data Science and ML Degree

Part 1…

medium.com

Greedy algorithms

Tree

100 days : Your Data Science and ML Degree — Part 2

100 days : Your Data Science and ML Degree — Part 2

Everything you need to know…

medium.com

Cluster Analysis using Python — Part 1

Cluster Analysis using Python — Part 1

With implementation/code

medium.datadriveninvestor.com

Machine Learning Clustering in detail with a project 2 ( part 1)

Day 28 : 60 days of Data Science and Machine Learning Series

ML Clustering Project 2 ( Part 1)..

medium.com

Linked List

Graph

Machine Learning Clustering in detail with a project 2 ( part 2)

Day 29 : 60 days of Data Science and Machine Learning Series

ML clustering Project 2 ( Part 2)..

medium.com

Multiple linear regression with a project

Day 32: 60 days of Data Science and Machine Learning Series

Regression Project 2..

medium.com

Matrix

Array

Principal Component Analysis with a project

Day 35: 60 days of Data Science and Machine Learning Series

Principal Component Analysis with a project..

medium.com

Binary Search

Implement Tokenization, POS tagging, Chunking, Named Entities Recognition ( NER)

Day 5: 30 days of Natural Language Processing Series with Projects

SpaCy with a project — Part 1

medium.com

Interval

Fast & Slow pointers

String

Language Classification with a project

Day 46: 60 days of Data Science and Machine Learning Series

Language Classification…

medium.com

Two Pointers

Python Crash Course — Part 1

Python Crash Course — Part 1

With Code Implementation…

medium.com

Python Crash Course — Part 2

Python Crash Course — Part 2

With Code Implementation…

medium.com

Sliding Window

Complete Advanced Python with Projects — Mega Compilation Part 6

Complete Advanced Python with Projects— Mega Compilation Part 6

Connect the dots…

medium.com

Heap

Complete Python Strings

Complete Python Strings — Part 1

With Implementation…

medium.datadriveninvestor.com

Python — Map, Classes, Functions and Arguments with Implementation

Python — Map, Classes, Functions and Arguments with Implementation

Use these hacks and techniques…

medium.datadriveninvestor.com

Company Wise Questions

Here we go —

Uber

Interval List Intersections (5 times): https://leetcode.com/problems/interval-list-intersections/
Construct K Palindrome Strings (5 times): https://leetcode.com/problems/construct-k-palindrome-strings/
Meeting Rooms II (5 times): https://leetcode.com/problems/meeting-rooms-ii/
Serialize and Deserialize Binary Tree (5 times): https://leetcode.com/problems/serialize-and-deserialize-binary-tree/
Group Anagrams (5 times): https://leetcode.com/problems/group-anagrams/
Add Two Numbers (4 times): https://leetcode.com/problems/add-two-numbers/
Construct Quad Tree (6 times): https://leetcode.com/problems/construct-quad-tree/
Merge Intervals (6 times): https://leetcode.com/problems/merge-intervals/
Find First and Last Position of Element in Sorted Array (6 times): https://leetcode.com/problems/find-first-and-last-position-of-element-in-sorted-array/
Minesweeper (6 times): https://leetcode.com/problems/minesweeper/
Reverse Linked List (6 times): https://leetcode.com/problems/reverse-linked-list/
Sliding Puzzle (6 times): https://leetcode.com/problems/sliding-puzzle/
Word Search II (4 times): https://leetcode.com/problems/word-search-ii/
Grumpy Bookstore Owner (4 times): https://leetcode.com/problems/grumpy-bookstore-owner/
Text Justification (12 times): https://leetcode.com/problems/text-justification/
Two Sum (9 times): https://leetcode.com/problems/two-sum/
Number of Islands (8 times): https://leetcode.com/problems/number-of-islands/
LRU Cache (8 times): https://leetcode.com/problems/lru-cache/
Reconstruct Itinerary (7 times): https://leetcode.com/problems/reconstruct-itinerary/
Rotate Image (7 times): https://leetcode.com/problems/rotate-image/

Advanced Python with Code Implementation

Advanced Python Made Easy — Part 6

With Implementation Code…

medium.datadriveninvestor.com

Google

Count Square Sub-matrices with All Ones (13 times): https://leetcode.com/problems/count-square-submatrices-with-all-ones/
Meeting Rooms II (12 times): https://leetcode.com/problems/meeting-rooms-ii/
Insert Interval (12 times): https://leetcode.com/problems/insert-interval/
Find Duplicate Subtrees (12 times): https://leetcode.com/problems/find-duplicate-subtrees/
Best Time to Buy and Sell Stock (12 times): https://leetcode.com/problems/best-time-to-buy-and-sell-stock/
Logger Rate Limiter (24 times): https://leetcode.com/problems/logger-rate-limiter/
Max Area of Island (20 times): https://leetcode.com/problems/max-area-of-island/
Car Fleet (16 times): https://leetcode.com/problems/car-fleet/
Add Two Numbers (13 times): https://leetcode.com/problems/add-two-numbers/
Longest Increasing Path in a Matrix (13 times): https://leetcode.com/problems/longest-increasing-path-in-a-matrix/
Max Value of Equation (13 times): https://leetcode.com/problems/max-value-of-equation/
My Calendar I (13 times): https://leetcode.com/problems/my-calendar-i/
Merge Intervals (13 times): https://leetcode.com/problems/merge-intervals/
Path With Minimum Effort (12 times): https://leetcode.com/problems/path-with-minimum-effort/
Decode String (11 times): https://leetcode.com/problems/decode-string/
Minimum Difference Between Largest and Smallest Value in Three Moves (11 times): https://leetcode.com/problems/minimum-difference-between-largest-and-smallest-value-in-three-moves/

Efficient Code and Optimization techniques for Python

Efficient Code and Optimization techniques for Python

With Implementation…

medium.datadriveninvestor.com

Maximum Points You Can Obtain from Cards (38 times): https://leetcode.com/problems/maximum-points-you-can-obtain-from-cards/
Guess the Word (37 times): https://leetcode.com/problems/guess-the-word/
Two Sum (29 times): https://leetcode.com/problems/two-sum/
Employee Importance (25 times): https://leetcode.com/problems/employee-importance/

Goldman Sachs

String Compression (9 times): https://leetcode.com/problems/string-compression/
Coin Change (8 times): https://leetcode.com/problems/coin-change/
Palindromic Substrings (8 times): https://leetcode.com/problems/palindromic-substrings/
Fraction Addition and Subtraction (7 times): https://leetcode.com/problems/fraction-addition-and-subtraction/
Knight Probability in Chessboard (6 times): https://leetcode.com/problems/knight-probability-in-chessboard/
Shortest Subarray with Sum at Least K (6 times): https://leetcode.com/problems/shortest-subarray-with-sum-at-least-k/
Height Checker (6 times): https://leetcode.com/problems/height-checker/
Fraction to Recurring Decimal (6 times): https://leetcode.com/problems/fraction-to-recurring-decimal/
Number of Islands (5 times): https://leetcode.com/problems/number-of-islands/
High Five (33 times): https://leetcode.com/problems/high-five/
Trapping Rain Water (30 times): https://leetcode.com/problems/trapping-rain-water/

60 days of Data Science and Machine Learning Series — Day 1

60 days of Data Science and Machine Learning Series — Day 1

Deep dive into Important topics, code, resources and implementations…

medium.datadriveninvestor.com

Delete and Earn (27 times): https://leetcode.com/problems/delete-and-earn/
Minimum Size Subarray Sum (18 times): https://leetcode.com/problems/minimum-size-subarray-sum/
Group Anagrams (18 times): https://leetcode.com/problems/group-anagrams/
First Unique Character in a String (14 times): https://leetcode.com/problems/first-unique-character-in-a-string/
Find Pivot Index (13 times): https://leetcode.com/problems/find-pivot-index/
Median of Two Sorted Arrays (12 times): https://leetcode.com/problems/median-of-two-sorted-arrays/
Count Number of Teams (12 times): https://leetcode.com/problems/count-number-of-teams/
Robot Bounded In Circle (29 times): https://leetcode.com/problems/robot-bounded-in-circle/
Design HashMap (11 times): https://leetcode.com/problems/design-hashmap/

Byte Dance

Course Schedule (3 times): https://leetcode.com/problems/course-schedule/
Merge k Sorted Lists (3 times): https://leetcode.com/problems/merge-k-sorted-lists/
Decode String (3 times): https://leetcode.com/problems/decode-string/
Similar String Groups (3 times): https://leetcode.com/problems/similar-string-groups/
Search a 2D Matrix II (3 times): https://leetcode.com/problems/search-a-2d-matrix-ii/
Basic Calculator (3 times): https://leetcode.com/problems/basic-calculator/
Subarray Sum Equals K (3 times): https://leetcode.com/problems/subarray-sum-equals-k/
Meeting Rooms II (5 times): https://leetcode.com/problems/meeting-rooms-ii/
Happy Number (4 times): https://leetcode.com/problems/happy-number/
Product of the Last K Numbers (4 times): https://leetcode.com/problems/product-of-the-last-k-numbers/
Binary Tree Longest Consecutive Sequence (4 times): https://leetcode.com/problems/binary-tree-longest-consecutive-sequence/
The Maze (4 times): https://leetcode.com/problems/the-maze/
Merge Intervals (4 times): https://leetcode.com/problems/merge-intervals/
Maximum Product of Three Numbers (3 times): https://leetcode.com/problems/maximum-product-of-three-numbers/

Underscores(_) in Python

Underscores(_) in Python

How to use them in your code…

medium.datadriveninvestor.com

Random Pick with Weight (3 times): https://leetcode.com/problems/random-pick-with-weight/
Palindrome Partitioning (3 times): https://leetcode.com/problems/palindrome-partitioning/
Subsets (6 times): https://leetcode.com/problems/subsets/
Number of Atoms (6 times): https://leetcode.com/problems/number-of-atoms/
Serialize and Deserialize Binary Tree (5 times): https://leetcode.com/problems/serialize-and-deserialize-binary-tree/
LRU Cache (5 times): https://leetcode.com/problems/Iru-cache/

Doordash

Design Browser History (6 times): https://leetcode.com/problems/design-browser-history/
Maximum Profit in Job Scheduling (6 times): https://leetcode.com/problems/maximum-profit-in-job-scheduling/
Number of Islands (5 times): https://leetcode.com/problems/number-of-islands/
Valid Sudoku (3 times): https://leetcode.com/problems/valid-sudoku/
Minimum Knight Moves (3 times): https://leetcode.com/problems/minimum-knight-moves/
Immediate Food Delivery II (2 times): https://leetcode.com/problems/immediate-food-delivery-ii/
Number of Subarrays with Bounded Maximum (2 times): https://leetcode.com/problems/number-of-subarrays-with-bounded-maximum/
Max Area of Island (21 times): https://leetcode.com/problems/max-area-of-island/
Employee Free Time (18 times): https://leetcode.com/problems/employee-free-time/

Python’s F-Strings

Python’s F-Strings

Complete implementation guide with code….

medium.datadriveninvestor.com

Count All Valid Pickup and Delivery Options (13 times): https://leetcode.com/problems/count-all-valid-pickup-and-delivery-options/
K Closest Points to Origin (9 times): https://leetcode.com/problems/k-closest-points-to-origin/
Course Schedule II (9 times): https://leetcode.com/problems/course-schedule-ii/
Meeting Scheduler (8 times): https://leetcode.com/problems/meeting-scheduler/
Longest Increasing Path in a Matrix (3 times): https://leetcode.com/problems/longest-increasing-path-in-a-matrix/
Maximum Performance of a Team (3 times): https://leetcode.com/problems/maximum-performance-of-a-team/
Course Schedule (2 times): https://leetcode.com/problems/course-schedule/
Analyze User Website Visit Pattern (2 times): https://leetcode.com/problems/analyze-user-website-visit-pattern/
Merge Intervals (2 times): https://leetcode.com/problems/merge-intervals/
Sudoku Solver (7 times): https://leetcode.com/problems/sudoku-solver/

Citadel

Count Number of Teams (2 times): https://leetcode.com/problems/count-number-of-teams/
Design In-Memory File System (2 times): https://leetcode.com/problems/design-in-memory-file-system/
LFU Cache (2 times): https://leetcode.com/problems/lfu-cache/
Wildcard Matching (2 times): https://leetcode.com/problems/wildcard-matching/
Consecutive Numbers Sum (13 times): https://leetcode.com/problems/consecutive-numbers-sum/
Number of Islands (7 times): https://leetcode.com/problems/number-of-islands/
Word Ladder (2 times): https://leetcode.com/problems/word-ladder/
Best Time to Buy and Sell Stock (2 times): https://leetcode.com/problems/best-time-to-buy-and-sell-stock/
Construct Binary Tree from Preorder and Inorder Traversal (2 times): https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/
Sliding Window Maximum (4 times): https://leetcode.com/problems/sliding-window-maximum/
Expression Add Operators (3 times): https://leetcode.com/problems/expression-add-operators/
Open the Lock (3 times): https://leetcode.com/problems/open-the-lock/
Integer Break (2 times): https://leetcode.com/problems/integer-break/

Lyft

Range Sum Query 2D — Immutable (4 times): https://leetcode.com/problems/range-sum-query-2d-immutable/
Word Ladder (3 times): https://leetcode.com/problems/word-ladder/
Asteroid Collision (3 times): https://leetcode.com/problems/asteroid-collision/
Reorder List (2 times): https://leetcode.com/problems/reorder-list/
Max Stack (7 times): https://leetcode.com/problems/max-stack/
Design Search Autocomplete System (4 times): https://leetcode.com/problems/design-search-autocomplete-system/
House Robber (4 times): https://leetcode.com/problems/house-robber/
Merge Intervals (4 times): https://leetcode.com/problems/merge-intervals/
Number of 1 Bits (3 times): https://leetcode.com/problems/number-of-1-bits/
Move Zeroes (3 times): https://leetcode.com/problems/move-zeroes/
Valid Anagram (3 times): https://leetcode.com/problems/valid-anagram/
Reverse Linked List (3 times): https://leetcode.com/problems/reverse-linked-list/
Beautiful Arrangement (3 times): https://leetcode.com/problems/beautiful-arrangement/
Two Sum (3 times): https://leetcode.com/problems/two-sum/
String Compression (3 times): https://leetcode.com/problems/string-compression/
LRU Cache (3 times): https://leetcode.com/problems/lru-cache/
Decode String (3 times): https://leetcode.com/problems/decode-string/
3Sum (3 times): https://leetcode.com/problems/3sum/
Maximum Subarray (3 times): https://leetcode.com/problems/maximum-subarray/
Decode Ways (4 times): https://leetcode.com/problems/decode-ways/
Product of Array Except Self (2 times): https://leetcode.com/problems/product-of-array-except-self/
Word Ladder II (2 times): https://leetcode.com/problems/word-ladder-ii/
Water and Jug Problem (2 times): https://leetcode.com/problems/water-and-jug-problem/
Minimum Window Substring (2 times): https://leetcode.com/problems/minimum-window-substring/
Read N Characters Given Read4 II — Call multiple times (9 times): https://leetcode.com/problems/read-n-characters-given-read4-ii-call-multiple-times/

Airbnb

Design In-Memory File System (2 times): https://leetcode.com/problems/design-in-memory-file-system/
Combination Sum (10 times): https://leetcode.com/problems/combination-sum/
Palindrome Pairs (10 times): https://leetcode.com/problems/palindrome-pairs/
Flatten 2D Vector (9 times): https://leetcode.com/problems/flatten-2d-vector/
Pour Water (5 times): https://leetcode.com/problems/pour-water/
Alien Dictionary (5 times): https://leetcode.com/problems/alien-dictionary/
Sliding Puzzle (3 times): https://leetcode.com/problems/sliding-puzzle/
IP to CIDR (3 times): https://leetcode.com/problems/ip-to-cidr/
Flatten Nested List Iterator (3 times): https://leetcode.com/problems/flatten-nested-list-iterator/
Maximum Profit in Job Scheduling (2 times): https://leetcode.com/problems/maximum-profit-in-job-scheduling/
Coin Change (2 times): https://leetcode.com/problems/coin-change/
Smallest Common Region (2 times): https://leetcode.com/problems/smallest-common-region/
Shortest Path to Get All Keys (2 times): https://leetcode.com/problems/shortest-path-to-get-all-keys/

Snapchat

Design Search Autocomplete System (2 times): https://leetcode.com/problems/design-search-autocomplete-system/
Find the Celebrity (2 times): https://leetcode.com/problems/find-the-celebrity/
One Edit Distance (2 times): https://leetcode.com/problems/one-edit-distance/
Longest Common Prefix (3 times): https://leetcode.com/problems/longest-common-prefix/
Best Time to Buy and Sell Stock (3 times): https://leetcode.com/problems/best-time-to-buy-and-sell-stock/
Find All Anagrams in a String (3 times): https://leetcode.com/problems/find-all-anagrams-in-a-string/
Number of Islands (3 times): https://leetcode.com/problems/number-of-islands/
Reconstruct Itinerary (2 times): https://leetcode.com/problems/reconstruct-itinerary/
Insert Delete GetRandom O(1) (2 times): https://leetcode.com/problems/insert-delete-getrandom-o1/
Sliding Window Median (2 times): https://leetcode.com/problems/sliding-window-median/
House Robber (4 times): https://leetcode.com/problems/house-robber/
Merge Intervals (4 times): https://leetcode.com/problems/merge-intervals/
Number of 1 Bits (3 times): https://leetcode.com/problems/number-of-1-bits/
Move Zeroes (3 times): https://leetcode.com/problems/move-zeroes/
Valid Anagram (3 times): https://leetcode.com/problems/valid-anagram/
Reverse Linked List (3 times): https://leetcode.com/problems/reverse-linked-list/
Beautiful Arrangement (3 times): https://leetcode.com/problems/beautiful-arrangement/
Two Sum (3 times): https://leetcode.com/problems/two-sum/
String Compression (3 times): https://leetcode.com/problems/string-compression/
LRU Cache (3 times): https://leetcode.com/problems/lru-cache/
Decode String (3 times): https://leetcode.com/problems/decode-string/
3Sum (3 times): https://leetcode.com/problems/3sum/
Maximum Subarray (3 times): https://leetcode.com/problems/maximum-subarray/
Trapping Rain Water (2 times): https://leetcode.com/problems/trapping-rain-water/
Shortest Bridge (2 times): https://leetcode.com/problems/shortest-bridge/
LRU Cache (8 times): https://leetcode.com/problems/lru-cache/
Word Search (7 times): https://leetcode.com/problems/word-search/
Course Schedule II (5 times): https://leetcode.com/problems/course-schedule-ii/
Decode String (4 times): https://leetcode.com/problems/decode-string/

Square

Edit Distance (3 times): https://leetcode.com/problems/edit-distance/
Multiply Strings (3 times): https://leetcode.com/problems/multiply-strings/
Add Strings (2 times): https://leetcode.com/problems/add-strings/
Game of Life (2 times): https://leetcode.com/problems/game-of-life/
Bus Routes (3 times): https://leetcode.com/problems/bus-routes/
Integer to English Words (3 times): https://leetcode.com/problems/integer-to-english-words/

Paypal

Binary Tree Level Order Traversal (2 times): https://leetcode.com/problems/binary-tree-level-order-traversal/
Daily Temperatures (2 times): https://leetcode.com/problems/daily-temperatures/
Pairs of Songs With Total Durations Divisible by 60 (2 times): https://leetcode.com/problems/pairs-of-songs-with-total-durations-divisible-by-60/
Reverse Words in a String III (2 times): https://leetcode.com/problems/reverse-words-in-a-string-iii/
Design Twitter (2 times): https://leetcode.com/problems/design-twitter/
Find the Duplicate Number (2 times): https://leetcode.com/problems/find-the-duplicate-number/
Valid Anagram (2 times): https://leetcode.com/problems/valid-anagram/
Invert Binary Tree (2 times): https://leetcode.com/problems/invert-binary-tree/
Intersection of Two Linked Lists (2 times): https://leetcode.com/problems/intersection-of-two-linked-lists/
House Robber (4 times): https://leetcode.com/problems/house-robber/
Merge Intervals (4 times): https://leetcode.com/problems/merge-intervals/
Number of 1 Bits (3 times): https://leetcode.com/problems/number-of-1-bits/
Move Zeroes (3 times): https://leetcode.com/problems/move-zeroes/
Valid Anagram (3 times): https://leetcode.com/problems/valid-anagram/
Reverse Linked List (3 times): https://leetcode.com/problems/reverse-linked-list/
Beautiful Arrangement (3 times): https://leetcode.com/problems/beautiful-arrangement/
Two Sum (3 times): https://leetcode.com/problems/two-sum/
String Compression (3 times): https://leetcode.com/problems/string-compression/
LRU Cache (3 times): https://leetcode.com/problems/lru-cache/
Decode String (3 times): https://leetcode.com/problems/decode-string/
3Sum (3 times): https://leetcode.com/problems/3sum/
Maximum Subarray (3 times): https://leetcode.com/problems/maximum-subarray/
LRU Cache (2 times): https://leetcode.com/problems/lru-cache/
Boats to Save People (2 times): https://leetcode.com/problems/boats-to-save-people/
Group Anagrams (2 times): https://leetcode.com/problems/group-anagrams/
Permutations (2 times): https://leetcode.com/problems/permutations/
Generate Parentheses (2 times): https://leetcode.com/problems/generate-parentheses/
Valid Parentheses (2 times): https://leetcode.com/problems/valid-parentheses/
ZigZag Conversion (2 times): https://leetcode.com/problems/zigzag-conversion/
Add Two Numbers (4 times): https://leetcode.com/problems/add-two-numbers/
Find K Closest Elements (4 times): https://leetcode.com/problems/find-k-closest-elements/
Merge Intervals (4 times): https://leetcode.com/problems/merge-intervals/
Text Justification (3 times): https://leetcode.com/problems/text-justification/

Databricks

Closest Leaf in a Binary Tree (3 times): https://leetcode.com/problems/closest-leaf-in-a-binary-tree/
Insert Delete GetRandom O(1) (2 times): https://leetcode.com/problems/insert-delete-getrandom-o1/
Text Justification (2 times): https://leetcode.com/problems/text-justification/
Trapping Rain Water (2 times): https://leetcode.com/problems/trapping-rain-water/
Merge k Sorted Lists (2 times): https://leetcode.com/problems/merge-k-sorted-lists/
Maximum Profit in Job Scheduling (4 times): https://leetcode.com/problems/maximum-profit-in-job-scheduling/
Web Crawler Multithreaded (3 times): https://leetcode.com/problems/web-crawler-multithreaded/

Dropbox

Number of Provinces (5 times): https://leetcode.com/problems/number-of-provinces/
LRU Cache (5 times): https://leetcode.com/problems/lru-cache/
Web Crawler Multithreaded (4 times): https://leetcode.com/problems/web-crawler-multithreaded/
Game of Life (4 times): https://leetcode.com/problems/game-of-life/
Sliding Window Maximum (4 times): https://leetcode.com/problems/sliding-window-maximum/
Design Phone Directory (2 times): https://leetcode.com/problems/design-phone-directory/
House Robber (4 times): https://leetcode.com/problems/house-robber/
Merge Intervals (4 times): https://leetcode.com/problems/merge-intervals/
Number of 1 Bits (3 times): https://leetcode.com/problems/number-of-1-bits/
Move Zeroes (3 times): https://leetcode.com/problems/move-zeroes/
Valid Anagram (3 times): https://leetcode.com/problems/valid-anagram/
Reverse Linked List (3 times): https://leetcode.com/problems/reverse-linked-list/
Beautiful Arrangement (3 times): https://leetcode.com/problems/beautiful-arrangement/
Two Sum (3 times): https://leetcode.com/problems/two-sum/
String Compression (3 times): https://leetcode.com/problems/string-compression/
LRU Cache (3 times): https://leetcode.com/problems/lru-cache/
Decode String (3 times): https://leetcode.com/problems/decode-string/
3Sum (3 times): https://leetcode.com/problems/3sum/
Maximum Subarray (3 times): https://leetcode.com/problems/maximum-subarray/
Number of Valid Words for Each Puzzle (15 times): https://leetcode.com/problems/number-of-valid-words-for-each-puzzle/
Find Duplicate File in System (9 times): https://leetcode.com/problems/find-duplicate-file-in-system/
Grid Illumination (6 times): https://leetcode.com/problems/grid-illumination/

Asana

Validate Binary Search Tree (5 times): https://leetcode.com/problems/validate-binary-search-tree/
K Closest Points to Origin (3 times): https://leetcode.com/problems/k-closest-points-to-origin/
Product of Array Except Self (5 times): https://leetcode.com/problems/product-of-array-except-self/

Akuna Capital

Decode Ways (6 times): https://leetcode.com/problems/decode-ways/
Strobogrammatic Number II (6 times): https://leetcode.com/problems/strobogrammatic-number-ii/
Backspace String Compare (6 times): https://leetcode.com/problems/backspace-string-compare/
Find Largest Value in Each Tree Row (6 times): https://leetcode.com/problems/find-largest-value-in-each-tree-row/
Letter Combinations of a Phone Number (6 times): https://leetcode.com/problems/letter-combinations-of-a-phone-number/
Design Circular Queue (6 times): https://leetcode.com/problems/design-circular-queue/
Sort List (6 times): https://leetcode.com/problems/sort-list/
Island Perimeter (6 times): https://leetcode.com/problems/island-perimeter/
Path Sum II (6 times): https://leetcode.com/problems/path-sum-ii/
Monotonic Array (6 times): https://leetcode.com/problems/monotonic-array/
Sliding Window Maximum (3 times): https://leetcode.com/problems/sliding-window-maximum/
Maximum Product Subarray (3 times): https://leetcode.com/problems/maximum-product-subarray/
Validate Binary Search Tree (10 times): https://leetcode.com/problems/validate-binary-search-tree/
Binary Tree Vertical Order Traversal (10 times): https://leetcode.com/problems/binary-tree-vertical-order-traversal/
Max Consecutive Ones III (10 times): https://leetcode.com/problems/max-consecutive-ones-iii/
Remove All Adjacent Duplicates in String II (10 times): https://leetcode.com/problems/remove-all-adjacent-duplicates-in-string-ii/
Diagonal Traverse (9 times): https://leetcode.com/problems/diagonal-traverse/
Check Completeness of a Binary Tree (9 times): https://leetcode.com/problems/check-completeness-of-a-binary-tree/
Nested List Weight Sum (9 times): https://leetcode.com/problems/nested-list-weight-sum/
Permutations (8 times): https://leetcode.com/problems/permutations/
Course Schedule (8 times): https://leetcode.com/problems/course-schedule/
Reverse Linked List (8 times): https://leetcode.com/problems/reverse-linked-list/
Palindrome Linked List (8 times): https://leetcode.com/problems/palindrome-linked-list/
Strobogrammatic Number (8 times): https://leetcode.com/problems/strobogrammatic-number/
First Missing Positive (8 times): https://leetcode.com/problems/first-missing-positive/
Construct Binary Tree from String (8 times): https://leetcode.com/problems/construct-binary-tree-from-string/
Generate Parentheses (8 times): https://leetcode.com/problems/generate-parentheses/
Median of Two Sorted Arrays (8 times): https://leetcode.com/problems/median-of-two-sorted-arrays/
Missing Ranges (8 times): https://leetcode.com/problems/missing-ranges/
Range Sum Query 2D — Immutable (8 times): https://leetcode.com/problems/range-sum-query-2d-immutable/
Populating Next Right Pointers in Each Node (8 times): https://leetcode.com/problems/populating-next-right-pointers-in-each-node/
Reverse Integer (8 times): https://leetcode.com/problems/reverse-integer/
Minimum Cost For Tickets (8 times): https://leetcode.com/problems/minimum-cost-for-tickets/
Minimum Knight Moves (8 times): https://leetcode.com/problems/minimum-knight-moves/
Sum Root to Leaf Numbers (8 times): https://leetcode.com/problems/sum-root-to-leaf-numbers/
Palindromic Substrings (8 times): https://leetcode.com/problems/palindromic-substrings/
First Unique Character in a String (7 times): https://leetcode.com/problems/first-unique-character-in-a-string/
N-Queens (7 times): https://leetcode.com/problems/n-queens/
Contiguous Array (6 times): https://leetcode.com/problems/contiguous-array/
Design Tic-Tac-Toe (6 times): https://leetcode.com/problems/design-tic-tac-toe/
Binary Tree Paths (6 times): https://leetcode.com/problems/binary-tree-paths/
Find All Anagrams in a String (6 times): https://leetcode.com/problems/find-all-anagrams-in-a-string/
Kth Smallest Element in a BST (6 times): https://leetcode.com/problems/kth-smallest-element-in-a-bst/
Robot Room Cleaner (6 times): https://leetcode.com/problems/robot-room-cleaner/
Binary Tree Level Order Traversal (7 times): https://leetcode.com/problems/binary-tree-level-order-traversal/
Read N Characters Given Read4 (7 times): https://leetcode.com/problems/read-n-characters-given-read4/
Path Sum (7 times): https://leetcode.com/problems/path-sum/
Find Pivot Index (7 times): https://leetcode.com/problems/find-pivot-index/
Intersection of Two Arrays (7 times): https://leetcode.com/problems/intersection-of-two-arrays/
Can Place Flowers (7 times): https://leetcode.com/problems/can-place-flowers/
Kth Smallest Element in a Sorted Matrix (7 times): https://leetcode.com/problems/kth-smallest-element-in-a-sorted-matrix/

Twitter

Minimum Swaps to Group All 1’s Together (3 times): https://leetcode.com/problems/minimum-swaps-to-group-all-1s-together/
Meeting Rooms II (3 times): https://leetcode.com/problems/meeting-rooms-ii/
The Skyline Problem (3 times): https://leetcode.com/problems/the-skyline-problem/
Word Search II (3 times): https://leetcode.com/problems/word-search-ii/
Merge Intervals (3 times): https://leetcode.com/problems/merge-intervals/
Merge k Sorted Lists (3 times): https://leetcode.com/problems/merge-k-sorted-lists/
Insert Delete GetRandom O(1) (7 times): https://leetcode.com/problems/insert-delete-getrandom-o1/
Maximal Square (6 times): https://leetcode.com/problems/maximal-square/
K-diff Pairs in an Array (5 times): https://leetcode.com/problems/k-diff-pairs-in-an-array/
The kth Factor of n (4 times): https://leetcode.com/problems/the-kth-factor-of-n/
Two Sum (4 times): https://leetcode.com/problems/two-sum/
Minimum Increment to Make Array Unique (4 times): https://leetcode.com/problems/minimum-increment-to-make-array-unique/
Find Median from Data Stream (4 times): https://leetcode.com/problems/find-median-from-data-stream/
Find Pivot Index (3 times): https://leetcode.com/problems/find-pivot-index/
Minimum Knight Moves (2 times): https://leetcode.com/problems/minimum-knight-moves/
Tweet Counts Per Frequency (38 times): https://leetcode.com/problems/tweet-counts-per-frequency/
Design Log Storage System (8 times): https://leetcode.com/problems/design-log-storage-system/
Insert Interval (7 times): https://leetcode.com/problems/insert-interval/
Maximum Number of Occurrences of a Substring (7 times): https://leetcode.com/problems/maximum-number-of-occurrences-of-a-substring/
Reaching Points (7 times): https://leetcode.com/problems/reaching-points/

Twilio

Sort Array by Increasing Frequency (3 times): https://leetcode.com/problems/sort-array-by-increasing-frequency/
Reconstruct Itinerary (3 times): https://leetcode.com/problems/reconstruct-itinerary/
Group Anagrams (3 times): https://leetcode.com/problems/group-anagrams/
House Robber (4 times): https://leetcode.com/problems/house-robber/
Merge Intervals (4 times): https://leetcode.com/problems/merge-intervals/
Number of 1 Bits (3 times): https://leetcode.com/problems/number-of-1-bits/
Move Zeroes (3 times): https://leetcode.com/problems/move-zeroes/
Valid Anagram (3 times): https://leetcode.com/problems/valid-anagram/
Reverse Linked List (3 times): https://leetcode.com/problems/reverse-linked-list/
Beautiful Arrangement (3 times): https://leetcode.com/problems/beautiful-arrangement/
Two Sum (3 times): https://leetcode.com/problems/two-sum/
String Compression (3 times): https://leetcode.com/problems/string-compression/
LRU Cache (3 times): https://leetcode.com/problems/lru-cache/
Decode String (3 times): https://leetcode.com/problems/decode-string/
3Sum (3 times): https://leetcode.com/problems/3sum/
Maximum Subarray (3 times): https://leetcode.com/problems/maximum-subarray/
LRU Cache (2 times): https://leetcode.com/problems/lru-cache/
Text Justification (15 times): https://leetcode.com/problems/text-justification/
Subarray Sums Divisible by K (7 times): https://leetcode.com/problems/subarray-sums-divisible-by-k/
Letter Combinations of a Phone Number (5 times): https://leetcode.com/problems/letter-combinations-of-a-phone-number/

Curated List — The Top & Most Frequently Asked Coding Questions You Should Practice

Solve these to crack (any) tech interview ….

medium.datadriveninvestor.com

System Design

All the Complete System Design Series Parts —

1. System design basics

2. Horizontal and vertical scaling

3. Load balancing and Message queues

4. High level design and low level design, Consistent Hashing, Monolithic and Microservices architecture

5. Caching, Indexing, Proxies

6. Networking, How Browsers work, Content Network Delivery ( CDN)

7. Database Sharding, CAP Theorem, Database schema Design

8. Concurrency, API, Components + OOP + Abstraction

9. Estimation and Planning, Performance

10. Map Reduce, Patterns and Microservices

11. SQL vs NoSQL and Cloud

12. Most Popular System Design Questions

Github —

Complete-System-Design/README.md at main · Coder-World04/Complete-System-Design

This repository contains everything you need to become proficient in System Design Topics you should know in System…

github.com

Design a concurrent Hashmap
Design an ATM Machine system which can support massive amount of transactions
Design Airport Baggage system
Design a Credit Card Authorization System

Major Compilation : Best Notebooks on Kaggle — Part 1

Major Compilation : Best Notebooks on Kaggle — Part 1

Notebooks from which you will learn the most…

medium.com

Design Uber
Design a logging system
Design Google Maps
Design a Video Conferencing System
Design a file storage service
Design a video streaming service
Design a chat service
Design a ride-sharing service
Design a URL shortening service

Python projects —

Complete Python And Projects — Mega Compilation

Everything that you need to know in Python with Projects…

medium.com

Design a social media service
Design a social message board
Design Flight Information Display system
Design a conference room booking system

Part 2 of Data Science and ML mega series ( Day 21 — Day 35) can be found here —

Data Science And Machine Learning Projects — Mega Compilation Part 2

Part 2 …

medium.com

Design newsfeed feature of Facebook
Design an efficient Mail delivery system
Design like/dislike feature at Youtube scale.
Design Instagram.
Design Tik-Tok
Design twitter

Part 3 of Data Science and M Lmega series ( Day 36 — Day 48) can be found here —

Data Science And Machine Learning Projects — Mega Compilation Part 3

Part 3…

medium.com

Design metas newsfeed with live posts
Design a Limited Time Deals
Design Twitter’s trending topics
Design a system that counts the number of clicks on YouTube videos
Design Gmail
Design a global system to upgrade software on a fleet of machines
Design a recommendation system
Design a food sharing application
Design an API for a tic tac toe game
Design payment module for Uber app
Design a smart meter system
Build Cart as a service

Complete Data Preprocessing and Data Visualization with Projects — Mega Compilation Part 2

Complete Data Preprocessing and Data Visualization with Projects — Mega Compilation Part 2

Connect the dots…

medium.com

Design comment system
Design flight system
Design Tinder
Design survey site like surveymonkey
Design a geographically partitioned multi-player card game.
Design a kind of kindle fire application
Design Truecaller type of system
Design performance management system (appraisal workflow system) that can be used across companies.

The Most Hilarious Code Comments Ever

The Most Hilarious Code Comments Ever

Programmer Humor: Yes, coders actually wrote them!

medium.datadriveninvestor.com

Design Instant Messenger.
Design a CDN network
Design a Google document system
Design a random ID generation system
Design a key-value database
Design the Facebook news feed function
Design a realtime Video chat like Google Duo
Design News paper & Magazine subscription system
Design a system like Hackerrank/Top Coder
Design an API Rate Limiter
Design a proximity server
Design a Type-Ahead service
Design a traffic control system
Design amazon’s frequently viewed product page

Build Machine Learning Pipelines( With Code)

Build Machine Learning Pipelines( With Code) — Part 1

Complete implementation…

medium.datadriveninvestor.com

Design a toll system for highways.
Design URL Shortener.
Design an online poker game for multiplayer.
Design a graph search function
Design a picture sharing system
Design an API Rate Limiter system for GitHub or Firebase sites
Design a search engine
Design a recommendation system
Design What’s up
Discussion and designing LRU cache.

Recurrent Neural Network with Keras

Recurrent Neural Network with Keras

Project Implementation and cheatsheet…

medium.datadriveninvestor.com

Design a forum-like systems like Quora, Reddit or HackerNews.
Design the Facebook timeline function
Design a function to return the top k requests during past time interval
Design an online multiplayer card game

Custom Layers in Keras

Custom Layers in Keras

Code implementation …

medium.datadriveninvestor.com

Design a website like Pastebin.
Design Google’s Web Crawler
Design Zoom
Design Twitter
Design a recommendation system for products.
Design a tinyurl system
Design Paypal
Design Air traffic control system
Design Google Maps
Design Grammarly
Design AirBNB
Design a vending machine in Java
Design a traffic control system
Design a limit order book for trading systems
Design Online Examination Portal
Design RedBus
Design BookMyShow
Design a garbage collection system.
Design a system to capture unique addresses in the entire world
Design an elevator system
Design an e-commerce website
Design an e-commerce website using microservices

Curated List — The Top & Most Frequently Asked Coding Questions You Should Practice

Curated List — The Top & Most Frequently Asked Coding Questions You Should Practice

Solve these to crack (any) tech interview ….

medium.datadriveninvestor.com

Design Domain Backdooring system
Design Amazon Locker
Design Movies Review Aggregator System
Design offline caching system for Ecommerce platform
Design Amazon E-commerce
Design Online chess game/Multiplayer game
Design gaming platform.
Design a last-mile delivery platform
Design Foodpanda/Zomato/Swiggy/
Design Meeting Calendar system
Design Spotify
Design Promo Code API
Design Vending machine
Design splitwise
Design Google pay at scale
Design a Job schedular
Design Meeting Scheduler
Design Debugger
Design Automatic Parking System
Design malloc, free and garbage collection system.
Design a system for collaborating over a document
Design election commission architecture

ANN, Linear Regression, Decision Tree Regression and Random Forest with a project

Day 56: 60 days of Data Science and Machine Learning Series

ANN, Linear Regression, Decision Tree Regression and Random Forest with a project…

medium.com

Design a garbage collection system
Design a scalable web crawling system
Design the Facebook chat function
Design a trending topic system
Design Amazon Best Seller Item Service
Design a global chat service like Whatsapp or a facebook messenger.
Design dropbox’s architecture.
Design a picture sharing website.
Design a news feed
Design a product based on maps
Design commenting system
Design a ranking system.
Design Amazon Cart system
Design a url compression system
Design Elevator system.

Transfer learning and Text Classification

Day 60: 60 days of Data Science and Machine Learning Series

Transfer learning and Text Classification…

medium.com

Design distributed caching system.
Design Amazon Locker Service.
Design Dropbox or Google Drive

Natural Language Processing and Convolutions

Day 59: 60 days of Data Science and Machine Learning Series

NLP and Convolutions…

medium.com

Design Google Search
Design Facebook
Design Snapchat
Design Instagram
Design App-store
Design a music player application
Design a distributed LRU Cache

Bidirectional Encoder Representations from Transformers ( BERT) with a project

Day 50: 60 days of Data Science and Machine Learning Series

Bidirectional Encoder Representations from Transformers ( BERT)…

medium.com

Design subscription based sports website
Design Netflix
Design Quora
Design Lookahead system
Design Google Docs/ Collaborative Editing service
Design URL Shortner service
Design Whatsapp

Quick Recap : 30 days of Natural Language Processing ( NLP) with Projects Series

Quick Recap : 30 days of Natural Language Processing ( NLP) with Projects Series

Connect the dots …

medium.com

Design a Latency Management System
Design a Library Management System
Design a Notification service
Design ESPN/Cricinfo/Cricbuzz
Design Uber

30 days of Data Analytics Series —

Day 1 : Data Analytics basics and kickstart of Data analytics with projects series

Day 2: Business Understanding — Data Driven Decision Making, Descriptive Analysis, Predictive Analysis, Diagnostic Analysis, Prescriptive Analysis

Day 3 : Data Analytics Ecosystem — Data Life Cycle, Data Analysis complete process ( most important things)

Day 4 : Probability, Conditional Probability, Binomial Distribution, Probability Density Function, Sampling Distribution

Day 5 : Statistics

Day 6 : Basic and Advanced SQL

Day 7 : Data Collection, Data Cleaning and Python

Day 8 : Pandas and Numpy

Day 9 : Data Manipulation

Day 10 : Data Visualization — Part 1

Day 11 : Project 1 : Data Visualization — Part 2

Day 12 : Data Visualization — Part 3

Day 13: Tableau — Part 1

Day 14: Tableau — Part 2

Day 15: Tableau — Part 3

Tableau Project

Day 16 : Data Analysis Project 2

Day 17 : Data Analysis Project 3

Day 18: Data Analysis Project 4

Day 19: Data Analysis Project 5

Day 20 : Data Analysis Project 6

Categorical and Numerical Features

Missing Value Analysis

Fill the missing Values

Unique Value Analysis

Univariate Analysis

Bivariate Analysis

Multivariate Analysis

Correlation Analysis

Day 21 : Data Analysis Project 7

Data Profiling

Feature Engineering

GroupBy Features

Categorical and Numerical Features

Missing Value Analysis

Fill the missing Values

Unique Value Analysis

Univariate Analysis

Bivariate Analysis

Multivariate Analysis

Correlation Analysis

Day 22 : Data analysis Project 8

Linear Regression

Data Profiling

Feature Engineering

Sort Values

Categorical and Numerical Features

Missing Value Analysis

Unique Value Analysis

Univariate Analysis

Bivariate Analysis

Multivariate Analysis

Correlation Analysis

Correlation Coefficients

Take Complete Hands On Tableau Course : Link

Happy learning and keep coding :)

Some of the links are affiliates.

Follow for more updates, stay tuned and of-course let me end this post with a quote by Steve Jobs ;)

“Your work is going to fill a large part of your life, and the only way to be truly satisfied is to do what you believe is great work. And the only way to do great work is to love what you do. If you haven’t found it yet, keep looking. Don’t settle. As with all matters of the heart, you’ll know when you find it.”