Frequently asked leetcode questions
Prepare for your Microsoft software engineer interview with this comprehensive collection of 250+ LeetCode coding questions actually asked in recent Microsoft technical interviews, organized by frequency, difficulty, topic, and acceptance rate to help you focus on the most important problems.
Microsoft's technical interview process has evolved significantly over the years, with a strong emphasis on data structures and algorithms. Based on recent candidate experiences and official Microsoft interview guidelines, the company typically conducts multiple rounds of technical screening that test your problem-solving abilities, coding proficiency, and system design knowledge.
The interview process usually consists of an initial online assessment followed by several onsite or virtual rounds. Each technical round lasts 45-60 minutes and focuses on solving 1-2 coding problems while explaining your thought process. Microsoft interviewers evaluate not just whether you can solve the problem, but how you approach it, communicate your ideas, and optimize your solution.
Unlike some other tech giants, Microsoft places considerable weight on practical problem-solving and code quality. Interviewers often ask follow-up questions about edge cases, time and space complexity analysis, and alternative approaches. They want to see candidates who can write clean, production-ready code rather than just finding any working solution.
Microsoft also values candidates who demonstrate collaboration skills and can explain complex technical concepts clearly. During your interview, you'll be expected to think aloud, discuss trade-offs between different approaches, and respond constructively to hints and suggestions from your interviewer.
Based on analysis of thousands of interview experiences shared on LeetCode discussions, Blind, and other platforms, certain problems appear repeatedly in Microsoft interviews. These questions have been asked multiple times across different roles and interview rounds over the past three years.
Array and string manipulation questions form the foundation of Microsoft's coding interviews. These problems test your ability to work with basic data structures efficiently and handle edge cases properly.
Two Sum remains one of the most frequently asked questions in Microsoft's online assessments and phone screens. This problem tests your understanding of hash maps and your ability to optimize from a brute force solution to an efficient one-pass approach. Microsoft interviewers often follow up by asking about variations like Three Sum or handling duplicate elements.
Longest Substring Without Repeating Characters is another staple in Microsoft interviews, particularly for testing sliding window technique knowledge. This problem appears frequently in both online assessments and onsite rounds, and interviewers expect you to explain how the sliding window maintains valid state and handles character frequency tracking.
Product of Array Except Self challenges candidates to think creatively about array manipulation without using division. Microsoft uses this problem to evaluate your ability to build solutions using prefix and suffix products, and your understanding of space complexity optimization.
Microsoft has a strong preference for dynamic programming questions, especially in mid-level to senior engineer interviews. These problems test your ability to break down complex problems into subproblems and build solutions incrementally.
Longest Palindromic Substring appears regularly in Microsoft interviews as a classic dynamic programming problem. Interviewers use this to assess your understanding of 2D DP tables and your ability to optimize space complexity. They often ask candidates to explain the difference between the DP approach and the expand-around-center approach.
Coin Change is frequently used to test unbounded knapsack understanding. Microsoft interviewers particularly like this problem because it has clear real-world applications and allows for discussion of both top-down and bottom-up DP approaches.
Word Break challenges your string processing and dynamic programming skills simultaneously. This problem appears in various forms across Microsoft interviews and tests your ability to handle substring matching efficiently using memoization or tabulation.
Binary tree and graph traversal questions are essential in Microsoft interviews, reflecting the importance of these structures in real-world software systems.
Binary Tree Level Order Traversal is consistently asked in Microsoft interviews to test your understanding of BFS and queue data structures. Interviewers expect you to handle this problem cleanly and often follow up with variations like zigzag traversal or vertical order traversal.
Number of Islands serves as a fundamental graph problem that tests DFS and BFS skills. Microsoft uses this problem and its variations to evaluate your ability to model problems as graphs and implement traversal algorithms correctly.
Validate Binary Search Tree appears frequently because it tests your understanding of BST properties and recursive thinking. Microsoft interviewers use this to assess whether you can handle the nuances of maintaining valid ranges during tree traversal.
Linked list problems in Microsoft interviews focus on pointer manipulation and in-place modifications. Questions like Reverse Linked List, Merge Two Sorted Lists, and Add Two Numbers test your ability to handle node pointers carefully and avoid common pitfalls like losing references or creating cycles.
Microsoft often asks Linked List Cycle II to evaluate your understanding of Floyd's cycle detection algorithm. This problem appears regularly because it combines algorithmic knowledge with careful implementation of pointer arithmetic.
Stack-based problems like Valid Parentheses and Min Stack are common in Microsoft's early interview rounds. These questions test your understanding of LIFO operations and your ability to maintain auxiliary data structures for optimization.
Implement Queue using Stacks and its reverse appear frequently because they test your understanding of data structure properties and your ability to amortize operations for efficiency.
Microsoft values binary search proficiency highly, as it appears in many real-world systems. Problems like Search in Rotated Sorted Array, Find Minimum in Rotated Sorted Array, and Median of Two Sorted Arrays test your ability to apply binary search in non-standard scenarios.
Binary Search itself appears in various forms, and Microsoft interviewers expect candidates to implement it bug-free and explain why their particular boundary conditions are correct.
Advanced graph problems like Clone Graph, Course Schedule, and Word Ladder appear in mid-level and senior interviews. These problems test your ability to model real-world problems as graphs and apply appropriate traversal or topological sorting techniques.
Microsoft particularly favors Rotting Oranges and similar multi-source BFS problems because they reflect distributed system patterns common in Microsoft's infrastructure.
Microsoft's online assessment (OA) typically includes 2-3 coding problems that must be solved within 90 minutes. The OA is often the first technical filter, so performing well here is crucial for advancing to phone screens.
Recent OAs have included problems like Two Sum, Reverse String, Valid Palindrome, and Maximum Subarray. These problems are generally easier than onsite questions but require clean implementation and good time management.
Microsoft also includes questions about String Compression, Meeting Rooms, and Merge Intervals in their OAs. These problems test your ability to work with arrays and intervals efficiently.
The OA environment typically uses an IDE with test cases visible, and your code is evaluated on correctness, efficiency, and edge case handling. Microsoft expects solutions that pass all test cases including hidden ones, so thorough testing is essential.
Easy problems form the foundation of Microsoft's screening process. Questions like Two Sum, Valid Parentheses, Merge Two Sorted Lists, Best Time to Buy and Sell Stock, and Maximum Depth of Binary Tree appear regularly in phone screens and OAs.
While these problems are categorized as easy, Microsoft expects optimal solutions with clean code and proper handling of edge cases. Candidates should be able to discuss time and space complexity confidently.
The majority of Microsoft interview questions fall in the medium difficulty range. Problems like Longest Substring Without Repeating Characters, 3Sum, Container With Most Water, Group Anagrams, and Spiral Matrix are frequently asked.
Medium problems test your ability to combine multiple techniques and handle more complex logic. Microsoft interviewers expect you to start with a working solution and then optimize it based on feedback.
Hard problems typically appear in senior engineer interviews or later rounds. Questions like Median of Two Sorted Arrays, Word Ladder II, Trapping Rain Water, and Longest Valid Parentheses test advanced algorithmic knowledge.
For hard problems, Microsoft interviewers don't always expect perfect solutions immediately. They value the problem-solving approach, ability to break down the problem, and willingness to discuss trade-offs.
Effective preparation for Microsoft interviews requires a structured approach focusing on the most commonly asked problem patterns. Rather than attempting to solve every LeetCode problem, focus on mastering the core patterns that appear repeatedly in Microsoft interviews.
Start with easy problems to build confidence and ensure you have solid fundamentals. Spend 1-2 weeks solving 30-40 easy problems covering arrays, strings, linked lists, and basic tree traversals. Focus on writing clean code and explaining your approach clearly.
Move to medium problems once you're comfortable with easy ones. Dedicate 4-6 weeks to solving 100-150 medium problems, focusing heavily on dynamic programming, graph algorithms, and tree problems. These topics appear most frequently in actual Microsoft interviews.
Practice hard problems selectively in your final 2-3 weeks of preparation. Choose 20-30 hard problems that appear in Microsoft interview reports and work through them thoroughly, ensuring you understand the optimal approaches.
Dynamic Programming deserves special attention for Microsoft interviews. Practice problems with different DP patterns including linear DP, 2D DP, unbounded knapsack, and string matching. Microsoft interviewers often start with a brute force recursive solution and expect you to optimize it using memoization or tabulation.
Graph algorithms including BFS, DFS, topological sort, and union-find are crucial. Microsoft's distributed systems and cloud infrastructure make graph problems particularly relevant. Practice modeling problems as graphs and selecting the appropriate traversal strategy.
Tree algorithms should be second nature. Master all tree traversal techniques including inorder, preorder, postorder, level order, and Morris traversal. Understand BST properties thoroughly and practice both recursive and iterative implementations.
Conduct mock interviews using platforms that simulate real interview conditions. Practice explaining your thought process out loud and writing code on a whiteboard or in a plain text editor without IDE assistance.
Time yourself strictly during practice sessions. Microsoft interviews are typically 45-60 minutes, and you need to solve problems efficiently while communicating clearly. Practice reduces anxiety and helps you develop good time management habits.
Candidates who succeed in Microsoft interviews consistently report that practicing the most frequently asked questions made a significant difference. Many successful candidates mention that seeing similar problem patterns in their actual interviews helped them stay calm and solve problems efficiently.
One common theme in successful interview experiences is the importance of communication. Microsoft interviewers appreciate candidates who think aloud, discuss trade-offs, and respond well to hints. Even when candidates don't reach the optimal solution immediately, demonstrating strong problem-solving methodology often leads to positive outcomes.
Unsuccessful candidates often report either insufficient practice with medium-difficulty problems or poor time management during interviews. Some candidates also mention getting stuck on edge cases they hadn't considered during practice.
Microsoft's interview process shares similarities with other top tech companies but has distinct characteristics. Compared to Google's interview, Microsoft places slightly less emphasis on algorithmic complexity and more on practical problem-solving and code quality.
Unlike Amazon's emphasis on leadership principles and behavioral questions, Microsoft's technical rounds focus primarily on coding ability and system design. However, Microsoft does evaluate collaboration and communication skills throughout the technical interview.
Facebook's (Meta) and Microsoft have similar coding interview styles, with both companies favoring medium-difficulty LeetCode problems. However, Microsoft tends to ask more questions about Microsoft-specific technologies and products in later rounds.
Many LeetCode problems asked at Microsoft also appear in Google, Amazon's interview, and Meta interviews. This overlap means preparing for Microsoft simultaneously prepares you for other FAANG interviews.
Microsoft interviewers expect candidates to analyze time and space complexity accurately. Always start by stating your initial solution's complexity, then discuss potential optimizations. If your first solution is O(n²), think about how hash maps, sorting, or two pointers might reduce it to O(n) or O(n log n).
Space complexity optimization often comes up in follow-up questions. If you use O(n) auxiliary space, be prepared to discuss whether you can reduce it to O(1) by modifying the input in place or using clever pointer manipulation.
Microsoft values robust code that handles edge cases properly. Always consider empty inputs, single-element inputs, duplicate values, negative numbers, and overflow conditions. Discuss these edge cases with your interviewer before starting to code.
Test your solution mentally or with simple examples before declaring it complete. Walk through your code with a test case to catch off-by-one errors or null pointer exceptions.
Start every problem by clarifying requirements and asking questions about input constraints. Microsoft interviewers appreciate candidates who don't make assumptions and think about problem specifications carefully.
Explain your approach before coding. Give a high-level overview of your algorithm, discuss its complexity, and wait for your interviewer's feedback. This saves time if you're headed in the wrong direction.
While coding, narrate your thoughts and explain non-obvious logic. This helps interviewers follow your reasoning and makes it easier for them to provide helpful hints if you get stuck.
Jumping into code without discussing your approach first is a common mistake. Microsoft interviewers want to see your problem-solving process, not just a final solution. Spend 5-10 minutes discussing your approach before writing any code.
Ignoring edge cases or assuming inputs are always valid leads to incomplete solutions. Always validate inputs and handle boundary conditions explicitly in your code.
Writing overly complicated solutions when simpler ones exist suggests poor judgment. Microsoft values elegant, maintainable code. If your solution has deeply nested loops or complex conditional logic, consider whether there's a cleaner approach.
Going silent while coding makes it hard for interviewers to help you. Even if you're focused on implementation details, periodically explain what you're doing and why.
Getting defensive when receiving feedback or hints damages your evaluation. Microsoft interviewers provide hints to help you succeed. Accept them gracefully and adjust your approach accordingly.
Claiming your solution is optimal without proper analysis raises red flags. Always analyze complexity honestly and be open to the possibility that better solutions exist.
Microsoft's official careers page provides information about the interview process and what to expect. The Microsoft Learn platform offers free courses on data structures and algorithms that align with interview expectations.
LeetCode's company tag feature allows you to filter problems by companies, including Microsoft. The discussion section for each problem often contains interview experiences and frequency information from real candidates.
Blind and other anonymous professional networks have threads where candidates share recent Microsoft interview questions. These community-reported questions provide valuable insights into current interview trends.
LeetCode Premium provides access to company-specific question frequencies and acceptance rates. This investment often pays off by helping you focus on the most relevant problems.
HackerRank and CodeSignal offer Microsoft-style assessments that simulate the online assessment environment. Practicing in similar conditions helps you perform better on actual OAs.
Success in Microsoft coding interviews requires consistent practice, strategic preparation, and effective communication. Focus on mastering the fundamental data structures and algorithms that appear most frequently in actual interviews.
Build your skills progressively from easy to hard problems, spending most of your time on medium-difficulty questions where Microsoft interviews concentrate. Practice explaining your thought process clearly and writing clean, bug-free code under time pressure.
Remember that Microsoft interviewers evaluate not just your coding ability but also your problem-solving approach, communication skills, and ability to collaborate. Demonstrate these qualities throughout your interview, and you'll significantly improve your chances of receiving an offer.
Start your preparation today with the most frequently asked Microsoft LeetCode questions, practice consistently, and approach each problem as an opportunity to learn and improve. With dedicated effort and the right strategy, you can succeed in your Microsoft technical interview.
How many LeetCode problems should I solve for Microsoft interviews?
For effective Microsoft interview preparation, solving 150-200 problems is generally sufficient, with focus on medium-difficulty questions. Quality matters more than quantity—thoroughly understanding 150 problems is better than superficially attempting 500.
What is the acceptance rate for Microsoft interviews?
Microsoft's overall acceptance rate varies by role and experience level, but typically ranges from 1-2% of applicants who ultimately receive offers. The interview process includes multiple stages, each filtering candidates progressively.
Does Microsoft ask system design questions?
Yes, Microsoft includes system design rounds for mid-level and senior positions. These typically occur after coding rounds and evaluate your ability to design scalable systems, though the focus remains primarily on coding ability for junior roles.
How long should I prepare for Microsoft interviews?
Most candidates benefit from 2-3 months of dedicated preparation, practicing 2-3 hours daily. This timeframe allows you to build strong fundamentals and practice sufficient problems across all important topics.
Are Microsoft interview questions harder than other FAANG companies?
Microsoft's coding questions are generally comparable in difficulty to other FAANG companies, with most problems falling in the medium LeetCode difficulty range. The main differences lie in interview structure and follow-up questions rather than raw problem difficulty.
What programming languages does Microsoft prefer?
Microsoft allows candidates to use their preferred programming language for interviews. Popular choices include C++, Java, Python, and C#. Choose the language you're most comfortable with, as interviewers focus on your problem-solving ability rather than language-specific features.
How important is the Microsoft online assessment?
The online assessment is crucial as it serves as the initial technical filter. Strong OA performance significantly increases your chances of advancing to phone screens. Treat the OA seriously and ensure your solutions pass all test cases including edge cases.
Disclaimer: The interview questions and related data presented on this page are curated from publicly available sources, including GitHub repositories, LinkedIn posts, blogs, and community discussions. This content is intended solely for educational and interview preparation purposes. It does not claim to represent actual or official Microsoft interview questions, nor is it affiliated with or endorsed by Microsoft.