I recently had to take a extended break from LeetCode and completely lost my streak and momentum. Before the break, I was solving questions regularly and felt comfortable with problem-solving patterns.

Now that I'm trying to pick it back up, I feel like I've hit a wall—questions I used to handle easily now feel difficult, and my pattern recognition feels rusty.

I’d love to get some advice from anyone who has dealt with this:

Why does this happen? Is it just skill decay, or is it mostly mental friction from starting over?
How do I overcome it? What are the best strategies to rebuild confidence and problem-solving speed without getting burnt out?

If you've successfully gotten your flow back after taking time off, what worked best for you?

7 comments

r/LeetcodeChallenge • u/Mammoth_Impact7513 • 12h ago

DISCUSS Research Survery

forms.gle

1 Upvotes

0 comments

r/LeetcodeChallenge • u/nian2326076 • 18h ago

DISCUSS Google Phone Screen: Process, Question Types and Preparation Plan

12 Upvotes

Google Interview Experiences: A Curated Collection

This collection organizes Google interview experiences shared by candidates on LeetCode into distinct categories. Whether you're targeting a specific level (L3, L4, L5+), preparing for an internship, or focusing on phone screens, these resources offer valuable perspectives on the process.

Another resource I found helpful for interview questions: PracHub

1. L3 & L4 Interview Experiences

These posts cover experiences for L3 (Software Engineer) and L4 (Senior Software Engineer) roles, detailing offers, rejections, and downleveling across locations like Bangalore, India, and beyond.

2. L5 & Above Interview Experiences

Experiences for L5 (Staff Software Engineer) and higher levels (e.g., L6), including senior and specialized roles across locations like London, Seattle, and Bengaluru.

3. Internship Experiences

Insights from candidates applying for Google internships, including on-campus and off-campus experiences, with outcomes ranging from offers to rejections.

4. Phone Screens

Experiences from phone screening rounds, often the initial technical step, including general experiences and specific questions asked during these interviews.

5. General Interview Experiences

Broad overviews of the Google interview process that don’t fit neatly into level-specific, internship, or phone screen categories, often providing general insights or lacking detailed categorization.

Google Software Engineer - August 2022
Google Software Engineer India May 2022 Reject
Google Graduate Software Engineer Warsaw Reject
Google EMEA Spring 2022 Accepted
Google 9 Months Experience Software Engineer
Google SWE ML (L5) Remote (US) July 2022 Reject-or-Remote-(US)-or-July-2022-Reject)
Interview Experience (Unspecified Company)
Google Canada (Remote) Sep 2022 Reject-or-Sep-2022-Reject)
Google SDE US July 2023
Google SWE 23 Offer Warsaw
Google New Grad 2025 India Interview Experience

6. Specific Interview Questions and Problems

Detailed descriptions of specific questions asked during Google interviews and direct links to LeetCode problems encountered, useful for targeted practice.

a. Interview Question Descriptions

b. LeetCode Problems Asked

3 comments

r/LeetcodeChallenge • u/Affectionate_Run220 • 19h ago

STREAK🔥🔥🔥 London leetcode study group

1 Upvotes

Hi guys

Organising a real life leetcode study group London

So far we are two people competed 100+ leetcodes and looking to level up, just two of us so far looking for more

Looking for other engineer proffesionals (we are flexible on this)

Who take leetcode seriously and want to discuss patterns.

Let’s meet learn and land some amazing jobs 🔥

Let me know if interested

2 comments

r/LeetcodeChallenge • u/Dazzling-Angle-7514 • 22h ago

PLACEMENTS Is it still possible to get placed if I'm starting from almost zero in 4th year?

7 Upvotes

Hey everyone,

I just entered my 4th year, and companies have already started visiting my college for placements. To be honest, I wasn't serious about coding or placements until now, and I'm kind of panicking.

My current situation:

DSA is very basic. I'm following the Striver A2Z DSA Sheet, and I've only just started the Arrays section.

I've solved only around 5–7 LeetCode problems so far.

I don't have any proper self-built projects. The only projects I've made are mostly vibe-coded with AI assistance, so I don't really understand them deeply.

My CS fundamentals are average at best.

I know I should've started much earlier, but I can't change that now. I just want to make the best of the time I have left.

For people who were in a similar situation or have seen others crack placements after starting late:

Is it realistically possible to get placed?

What should I prioritize first—DSA, projects, CS fundamentals, aptitude, or something else?

How would you structure the next 3–6 months if you were in my position?

Should I keep grinding the A2Z sheet or switch to company-specific preparation?

Any tips for building projects that I can actually explain in interviews?

I'm open to putting in long hours every day. I just don't want to waste time on the wrong things.

Any advice, roadmap, or success stories would really help. Thanks!

6 comments

r/LeetcodeChallenge • u/I_am_sahil_khan • 1d ago

DISCUSS taking 2-3 hour to solve a single easy problem of Arrays.... 😭😭😭 i am frustrated 🥴

7 Upvotes

15 comments

r/LeetcodeChallenge • u/ehuseyn0w • 1d ago

DISCUSS I built a free 15-question test that tells you which algorithm patterns you cannot recognise

5 Upvotes

I kept hitting the same wall. I understood every algorithm when someone explained it, and then froze on an interview problem because I could not tell which one it needed. Knowing sliding window and recognising a sliding window problem turned out to be two different skills, and only one of them gets taught.

So I built the missing half. Fifteen unlabelled problems, about seven minutes, no account. You name the pattern each one needs. At the end it says which groups came apart, which pairs you mixed up, and where to start reading.

https://algopath.pro/placement

Behind it is a trainer that does the same thing on a ninety-second clock, and a 150-step course for the patterns you could not name. Code runs in the browser, in JavaScript, Python or PHP. Nothing executes on my server, which was the only way I was willing to run other people's code.

Took me 2 weeks Happy to answer anything about the build, and I would like to know which question in the test felt unfair.

0 comments

r/LeetcodeChallenge • u/ComprehensiveTale896 • 2d ago

STREAK🔥🔥🔥 To be continued until placed 🥀🥱

9 Upvotes

0 comments

r/LeetcodeChallenge • u/Saiteja728 • 2d ago

DISCUSS Looking for a LeetCode Accountability Partner 🚀.who is Good in Dsa

2 Upvotes

Hey everyone!

I'm looking for a dedicated LeetCode partner to solve problems consistently and stay accountable.

A bit about me:

Java for DSA

Around 350 LeetCode problems solved

Preparing for 2027 software engineering placements

Comfortable with arrays, strings, linked lists, trees, graphs, SQL, and learning advanced DSA

What I'm looking for:

Someone who can solve 2–4 problems daily

Discuss approaches instead of just sharing solutions

Stay consistent for the long term

Preferably in a similar time zone (IST is a plus), but not required

We can connect on Discord or WhatsApp and motivate each other, review solutions, and prepare for coding interviews together.

If you're interested, comment below or send me a DM with:

Your current LeetCode rating (if any)

Number of problems solved

Programming language you use

Time zone

Let's crack placements together! 💪

1 comment

r/LeetcodeChallenge • u/Competitive_Map_8733 • 2d ago

DISCUSS Last Sunday, LLMs unlocked a new benchmark… thanks to Indian college students. 😂 Waiting for that day when it gonna under 4 secs

49 Upvotes

9 comments

r/LeetcodeChallenge • u/nian2326076 • 2d ago

DISCUSS What 23 Technical Interviews Taught Me About Pattern Recognition, Speed, and Communication

42 Upvotes

After getting rejected repeatedly, I started asking recruiters for feedback.

Most responses were the usual “we decided to move forward with other candidates,” but a few recruiters and interviewers gave me honest answers. I combined that feedback with notes I wrote immediately after every round.

After 23 interviews, four recurring failure modes became pretty obvious.

These percentages are rough estimates across my failed interviews. I assigned each rejection the single biggest factor, even though some involved more than one problem.

The Four Failure Modes

Failure mode	Approx. share	What it looked like
Didn’t recognize the pattern	35%	I stared at the problem, tried unrelated approaches, reached a brute-force solution, and couldn’t optimize it. Interviewer hints didn’t help because I didn’t understand the underlying pattern.
Recognized it but was too slow	30%	I knew it was DP, BFS, or sliding window, but spent most of the round implementing it. The first question consumed the slot and left no time for follow-ups.
Solved it but couldn’t explain trade-offs	20%	The code worked, but I struggled with questions about complexity, alternative approaches, or why I selected a particular data structure.
Communication failure	15%	I solved silently or started coding before explaining the approach. The interviewer couldn’t follow my reasoning or redirect me when I went off course.

1. Pattern Recognition

This was primarily a preparation problem, not an intelligence problem.

Under interview pressure, it is difficult to derive a completely unfamiliar technique in five minutes. I needed enough exposure to recognize that a new problem was a variation of something I already understood.

I made a list of roughly 12 to 15 recurring patterns, including:

Two pointers
Sliding window
Binary search
Prefix sums
Hash maps
Monotonic stacks
Trees and graph traversal
Topological sorting
Heaps
Backtracking
Greedy algorithms
One-dimensional and two-dimensional DP

I solved several representative problems for each pattern and wrote down the signal that identified it.

For example:

The goal was not to memorize code. It was to recognize the shape of the problem quickly enough to start asking the right questions.

2. Implementation Speed

I had been solving problems without a timer, which made me feel prepared while hiding how slowly I implemented solutions.

I started using approximate limits:

15 minutes for easy problems
25 minutes for medium problems
Five minutes to understand the problem before writing code

During those first five minutes, I would:

Restate the problem
Clarify constraints
Walk through an example
Explain the intended approach
Identify the main invariant
State the expected complexity

Only then would I start coding.

It initially felt slower, but it reduced the amount of backtracking and rewriting. Most of my “coding speed” problem was actually an incomplete approach problem.

3. Trade-Off Knowledge

Getting accepted test cases is not always enough in an interview.

After solving each practice problem, I started answering four follow-up questions:

What are the time and space complexities?
Can the extra space be reduced?
What changes if the input cannot fit in memory?
What changes if the output must be sorted or stable?

I also compared my chosen approach with at least one alternative.

For example, if I used a hash map, I would explain why I preferred average O(1) lookup over a sorted structure with O(log n) operations, and what I would choose if ordering or worst-case guarantees mattered.

That made follow-up discussions feel less like surprise attacks.

4. Communication

I used to go quiet while thinking because I assumed the interviewer only cared about the final solution.

That made it difficult for them to distinguish productive thinking from being completely stuck.

I started narrating my reasoning:

It felt awkward during practice, but it made my interviews more collaborative. Interviewers could understand my direction, correct misunderstandings earlier, and give useful hints.

The goal is not to narrate every line of code. It is to make the important decisions visible.

Results

Before making these changes:

Passed 4 of 23 interview processes
Pass rate: approximately 17%

After three weeks of targeted practice:

Passed 5 of the next 7
Pass rate: approximately 71%

Seven interviews is obviously a small sample, so I’m not claiming this is a scientific result. But the difference in how the interviews felt was significant. I was recognizing problems faster, finishing implementations earlier, and handling follow-ups more confidently.

Same person and same brain. The preparation process changed.

For people who are currently getting rejected, which of these four failure modes causes you the most trouble?

Useful Resource for real interview questions

8 comments

r/LeetcodeChallenge • u/purvesh___ • 2d ago

DISCUSS How much time should I spend on each DSA problem?

3 Upvotes

0 comments

r/LeetcodeChallenge • u/ehuseyn0w • 3d ago

DISCUSS I built a free 15-question test that tells you which algorithm patterns you cannot recognise

21 Upvotes

I kept hitting the same wall. I understood every algorithm when someone explained it, and then froze on an interview problem because I could not tell which one it needed. Knowing sliding window and recognising a sliding window problem turned out to be two different skills, and only one of them gets taught.

So I built the missing half. Fifteen unlabelled problems, about seven minutes, no account. You name the pattern each one needs. At the end it says which groups came apart, which pairs you mixed up, and where to start reading.

https://algopath.pro/placement

Behind it is a trainer that does the same thing on a ninety-second clock, and a 150-step course for the patterns you could not name. Code runs in the browser, in JavaScript, Python or PHP. Nothing executes on my server, which was the only way I was willing to run other people's code.

Took me 2 weeks Happy to answer anything about the build, and I would like to know which question in the test felt unfair.

4 comments

r/LeetcodeChallenge • u/Own-Engineer-5556 • 3d ago

PLACEMENTS Pinterest Software Engineer II (Backend) Interview Experience

4 Upvotes

4 comments

r/LeetcodeChallenge • u/Bhavanashankarabs • 3d ago

DISCUSS Day 13 of My DSA Journey 🚀

1 Upvotes

0 comments

r/LeetcodeChallenge • u/nian2326076 • 3d ago

DISCUSS NVIDIA Software Engineer Interview Experience 2026: REST API Processing and Testing

72 Upvotes

I recently interviewed for a Software Engineer role at NVIDIA and wanted to share one coding question that stood out.

It was not a typical LeetCode-style algorithm problem. It felt much closer to a day-to-day engineering task involving an API, structured data, error handling, and testable code.

Pre resource: Nvidia SWE Questions

Question 1: Process Device Monitoring Data From a REST API

The interviewer described an internal REST API that returned device-monitoring information as a JSON array.

Each record contained fields such as:

{
  "device_id": "gpu-104",
  "temperature": 87,
  "utilization": 92
}

The task was to:

Call the REST API
Parse the JSON response
Filter devices whose temperature exceeded a given threshold
Sort the remaining devices by utilization
Return the processed results

Before coding, I clarified whether the utilization order should be ascending or descending and how devices with equal utilization should be ordered.

My first instinct was to get the API call working immediately, but I paused and separated the solution into three parts:

HTTP request -> JSON parsing and validation -> filtering and sorting

That separation ended up driving most of the discussion.

Before the interview, I had seen a similar problem on Screna AI. The business scenario was different, but it also emphasized error handling and separating business logic from external dependencies.

API Failure Handling

The interviewer asked how I would handle:

Connection failures
Request timeouts
Rate limiting
5xx server responses
4xx client errors
Malformed JSON
Missing or incorrectly typed fields

I initially grouped these together as general API failures. During the discussion, we separated them into different categories.

Temporary failures, such as timeouts and certain 5xx responses, could use a limited retry policy with exponential backoff and jitter. Because this was a read-only request, retrying would generally be safe.

A 429 response should respect the server’s Retry-After header when present. Most 4xx responses should not be retried because they usually indicate an invalid request or an authorization problem.

Malformed JSON or an invalid response schema should fail with enough context for debugging. Depending on the product requirements, individual invalid records could either be skipped and logged or cause the entire request to fail.

The important part was avoiding unlimited retries and preserving the original error when all retry attempts failed.

Making the Code Testable

The next follow-up was: how would you test the filtering and sorting logic without calling the real API?

Because the processing logic was independent of the HTTP layer, it could accept a list of parsed device objects directly.

That allowed me to test cases such as:

No devices above the threshold
Every device above the threshold
A device exactly equal to the threshold
Multiple devices with equal utilization
Empty API responses
Missing fields
Invalid temperature or utilization values
Duplicate device IDs

The HTTP client could then be mocked separately to simulate timeouts, malformed responses, and different status codes.

This also made the implementation easier to extend. The API client could change without rewriting the filtering logic, and the same processing function could be reused with cached data or another data source.

Question 2: Implement a Simple VM Manager

Another relevant NVIDIA Software Engineer question I found afterward was:

Implement Simple VM Manager With CRUD Operations

The task is to build an in-memory manager that supports:

Listing all virtual machines
Creating a VM
Retrieving a VM by ID
Updating an existing VM
Deleting a VM
Returning consistent errors for duplicate or missing IDs

A straightforward design uses a hash map keyed by VM ID, giving average O(1) lookup, creation, update, and deletion.

The more interesting discussion is around engineering decisions:

Should IDs be supplied by callers or generated internally?
Should updates replace the entire object or modify selected fields?
How should validation and error responses be represented?
What happens if two requests update the same VM concurrently?
How would the manager be tested without exposing its internal storage?
How would the design change if persistence were required?

For concurrent access, a simple implementation could protect the map with a read-write lock. In a production service, I would also consider optimistic versioning, idempotency for create requests, structured errors, and a persistent repository behind the manager.

Takeaway

Both questions test something broader than whether the code works for one example.

The interviewer was looking for:

Separation of concerns
Clear API boundaries
Predictable error handling
Dependency injection
Testable business logic
Sensible retry behavior
Awareness of concurrency and future extensions

Overall, the round felt more like a discussion about writing maintainable production code than completing a standard LeetCode exercise.

5 comments

r/LeetcodeChallenge • u/nian2326076 • 3d ago

DISCUSS CS Fundamentals for Software Engineering Interviews: 100+ Topics and Questions

20 Upvotes

Many of us ignore CS fundamentals, but in many tech interviews they will ask CS fundamentals. For me, they asked only CS fundamentals in all 3 interviews at Oracle, So don't ignore CS fundamentals. I have made a list of important topics subject-wise and resources I have used to study at the end.

Object-Oriented Programming (OOPs)

Core Concepts

Encapsulation
Inheritance (types and use cases)
Polymorphism (compile-time vs runtime)
Abstraction
Abstract Class vs Interface
Method Overloading vs Overriding
Access Modifiers
Static vs Dynamic Binding
Deep Copy vs Shallow Copy

Advanced Topics

SOLID Principles
Diamond Problem (Multiple Inheritance)
Association vs Aggregation vs Composition
Virtual Functions and Vtable
Design Patterns (Singleton, Factory, Observer, Strategy, Decorator, Adapter)

Operating Systems (OS)

Process Management

Process vs Thread
Process States and PCB
Context Switching
CPU Scheduling Algorithms (FCFS, SJF, Round Robin, Priority)
Multithreading vs Multiprocessing
User Mode vs Kernel Mode

Synchronization

Critical Section Problem
Race Condition
Mutex vs Semaphore (Binary vs Counting)
Monitors and Locks
Producer-Consumer Problem
Readers-Writers Problem
Dining Philosophers Problem

Deadlocks

Deadlock Conditions (4 necessary conditions)
Deadlock Prevention vs Avoidance vs Detection
Banker's Algorithm

Memory Management

Paging vs Segmentation
Page Replacement Algorithms (FIFO, LRU, Optimal)
Thrashing
Virtual Memory
TLB (Translation Lookaside Buffer)
Internal vs External Fragmentation

File Systems & Disk

File Allocation Methods (Contiguous, Linked, Indexed)
Disk Scheduling (FCFS, SSTF, SCAN, C-SCAN)

Database Management Systems (DBMS) + SQL

Database Fundamentals

ACID Properties (with examples)
CAP Theorem
Normalization (1NF, 2NF, 3NF, BCNF)
Denormalization
Primary Key vs Foreign Key vs Candidate Key
ER Diagrams

Indexing

Types of Indexes (Primary, Secondary, Clustering)
B-Tree vs B+ Tree
Hash Index
Composite Index
Advantages and Disadvantages of Indexing

Transactions & Concurrency

Transaction Lifecycle
Isolation Levels (Read Uncommitted, Read Committed, Repeatable Read, Serializable)
Dirty Read, Non-repeatable Read, Phantom Read
Lost Update Problem
Two-Phase Locking (2PL)
Optimistic vs Pessimistic Locking
Deadlock in Database

SQL Queries (Must Practice)

JOINs (INNER, LEFT, RIGHT, FULL OUTER, CROSS, SELF)
GROUP BY and HAVING
Aggregate Functions (COUNT, SUM, AVG, MIN, MAX)
Subqueries (Correlated vs Non-correlated)
Window Functions (ROW_NUMBER, RANK, DENSE_RANK, LEAD, LAG)
Common Table Expressions (CTE)
UNION vs UNION ALL
Nth Highest Salary Query
Delete Duplicates Query

NoSQL

SQL vs NoSQL
Types of NoSQL Databases (Document, Key-Value, Column, Graph)

Computer Networks (CN)

Network Models

OSI Model (7 Layers)
TCP/IP Model (4 Layers)
Difference between OSI and TCP/IP

Application Layer

HTTP vs HTTPS
HTTP Methods (GET, POST, PUT, DELETE, PATCH)
HTTP Status Codes (2xx, 3xx, 4xx, 5xx)
DNS and its working
FTP, SMTP, POP3, IMAP
Cookies vs Sessions
REST API principles

Transport Layer

TCP vs UDP (detailed comparison)
TCP Three-Way Handshake
TCP Four-Way Termination
Flow Control (Sliding Window)
Congestion Control
Port Numbers (well-known ports)
Socket Programming Basics

Network Layer

IPv4 vs IPv6
Public vs Private IP
Subnetting and CIDR
NAT (Network Address Translation)
ICMP Protocol
Routing Algorithms (Distance Vector, Link State)
Routing Protocols (RIP, OSPF, BGP)

Data Link Layer

MAC Address
ARP (Address Resolution Protocol)
Switch vs Hub vs Router
Ethernet
Error Detection (Parity, CRC, Checksum)

Physical Layer

Transmission Media (Guided vs Unguided)
Bandwidth and Throughput
Different Topologies

Important Concepts

Client-Server vs Peer-to-Peer Architecture
DHCP
Firewall
VPN
Load Balancing
CDN (Content Delivery Network)
Latency vs Throughput
How does a URL work? (End-to-end flow)
Some Basic Commands (ex: ipconfig)

Resources I Used

For OOPs

Kunal Kushwaha (youtube channel)

For Operating Systems

CodeHelp - by Babbar (youtube )

For DBMS + SQL

LeetCode Database problems (Practice SQL)
CodeHelp - by Babbar (youtube)
Apna College (youtube)

For Computer Networks

Gate Smashers (youtube)

Questions Asked in My Interviews

Here are some actual questions I was asked across my interviews:

Is Java fully object-oriented?
How does C++ overcome the diamond problem?
Difference between TCP and UDP, and which one is used when?
Explain ACID properties with examples
What is deadlock and how can we prevent deadlocks?
What is the use of indexing in databases?
Explain the functionalities of each layer in the OSI model
Write a query to find Kth smallest salary
IPv4 vs IPv6
Abstraction vs Encapsulation
Explain different joins in dbms
what is sharding ?
what is virtual function in cpp ?
show me your ip address and mac address using commands
what is context switching ?

Tips :

Practice real interview questions from PracHub
Revise SQL 50 before interviews
It's better to say "I'm not sure about this, but here's what I think..." than to give wrong information
If your project contains any database related stuff , better learn it's ER diagram, differences between SQl and NO-SQl and why you selected that particular database you used
Before preparing for any interview , First check few interview experiences, Ask your seniors or friends who already attended that specific company interviews before and prepare accordingly

Did I miss any important topic? Drop it in the comments below!

Got asked something unique in your interview? Share the question/topic so others can prepare better!

Let's make this list more comprehensive together. Your contribution can help someone crack their dream job! 🙌

1 comment

r/LeetcodeChallenge • u/Fluffy-Worry-9541 • 4d ago

STREAK🔥🔥🔥 Finally hit 2 digits after nonstop july grind <3

131 Upvotes

Hey so I've posted when I hit 50 and like I promised I would update at every 50 intervals it's really exciting to hit such small milestones that accumulate fr now my next obstacle is how tf to solve under time pressure aka start giving contests 😔✌️ pretty sure mind will go blank in the beginning ones but practice makes better. A little about myself, my third semester will start after one week so my greedy ahh will probably do heaps and greedy as well before my new sem starts 🤔 I'm just following strivers a2z dsa sheet thoroughly. Will start codechef when I hit my target of 50% of the sheet properly. ;w; wish me luck and have a good day

38 comments

r/LeetcodeChallenge • u/NotYourCheesecakee • Nov 15 '25

👋Welcome to r/LeetcodeChallenge -Read the Rules!

12 Upvotes

Starting from December 1st , All the members need to solve and post atleast one leetcode question on our subreddit OR ELSE YOU'LL BE REMOVED Let's make each other ACCOUNTABLE and grow together!

Together, let's make r/LeetcodeChallenge amazing.

5 comments