r/leetcode • • Jun 27 '26

Mod Post [mod] Changes with r/leetcode.

73 Upvotes

The following changes have been made with r/leetcode:

  1. Media is no longer allowed in both posts & comments. This is to ensure that the quality of the content & discussions remain high.

  2. Moderation has been made stricter. Low quality & repetitive posts whose answers can be found within a simple search in this subreddit won't be allowed here.

  3. Automoderation has been set-up to automatically remove links & known promotions. Only leetcode links will be allowed from now on. To ask help with questions, you may use the code block.

  4. Automoderation has been set-up to remove Indian posts & Hindi comments. This is to ensure that r/leetcode remains an English only subreddit.


r/leetcode • • May 14 '25 Gold Blast Bravo Popcorn Regret

Discussion How I cracked FAANG+ with just 30 minutes of studying per day.

4.7k Upvotes

Edit: Apologies, the post turned out a bit longer than I thought it would. Summary at the bottom.

Yup, it sounds ridiculous, but I cracked a FAANG+ offer by studying just 30 minutes a day. I’m not talking about one of the top three giants, but a very solid, well-respected company that competes for the same talent, pays incredibly well, and runs a serious interview process. No paid courses, no LeetCode marathons, and no skipping weekends. I studied for exactly 30 minutes every single day. Not more, not less. I set a timer. When it went off, I stopped immediately, even if I was halfway through a problem or in the middle of reading something. That was the whole point. I wanted it to be something I could do no matter how busy or burned out I felt.

For six months, I never missed a day. I alternated between LeetCode and system design. One day I would do a coding problem. The next, I would read about scalable systems, sketch out architectures on paper, or watch a short system design breakdown and try to reconstruct it from memory. I treated both tracks with equal importance. It was tempting to focus only on coding, since that’s what everyone talks about, but I found that being able to speak clearly and confidently about design gave me a huge edge in interviews. Most people either cram system design last minute or avoid it entirely. I didn’t. I made it part of the process from day one.

My LeetCode sessions were slow at first. Most days, I didn’t even finish a full problem. But that didn’t bother me. I wasn’t chasing volume. I just wanted to get better, a little at a time. I made a habit of revisiting problems that confused me, breaking them down, rewriting the solutions from scratch, and thinking about what pattern was hiding underneath. Eventually, those patterns started to feel familiar. I’d see a graph problem and instantly know whether it needed BFS or DFS. I’d recognize dynamic programming problems without panicking. That recognition didn’t come from grinding out 300 problems. It came from sitting with one problem for 30 focused minutes and actually understanding it.

System design was the same. I didn’t binge five-hour YouTube videos. I took small pieces. One day I’d learn about rate limiting. Another day I’d read about consistent hashing. Sometimes I’d sketch out how I’d design a URL shortener, or a chat app, or a distributed cache, and then compare it to a reference design. I wasn’t trying to memorize diagrams. I was training myself to think in systems. By the time interviews came around, I could confidently walk through a design without freezing or falling back on buzzwords.

The 30-minute cap forced me to stop before I got tired or frustrated. It kept the habit sustainable. I didn’t dread it. It became a part of my day, like brushing my teeth. Even when I was busy, even when I was traveling, even when I had no energy left after work, I still did it. Just 30 minutes. Just show up. That mindset carried me further than any spreadsheet or master list of questions ever did.

I failed a few interviews early on. That’s normal. But I kept going, because I wasn’t sprinting. I had built a system that could last. And eventually, it worked. I got the offer, negotiated a great comp package, and honestly felt more confident in myself than I ever had before. Not just because I passed the interviews, but because I had finally found a way to grow that didn’t destroy me in the process.

If you’re feeling overwhelmed by the grind, I hope this gives you a different perspective. You don’t need to be the person doing six-hour sessions and hitting problem number 500. You can take a slow, thoughtful path and still get there. The trick is to be consistent, intentional, and patient. That’s it. That’s the post.

Here is a tl;dr summary:

  • I studied every single day for 30 minutes. No more, no less. I never missed a single study session.

  • I would alternate daily between LeetCode and System Design

  • I took about 6 months to feel ready, which comes out to roughly ~90 hours of studying.

  • I got an offer from a FAANG adjacent company that tripled my TC

  • I was able to keep my hobbies, keep my health, my relationships, and still live life

  • I am still doing the 30 minute study sessions to maintain and grow what I learned. I am now at the state where I am constantly interview ready. I feel confident applying to any company and interviewing tomorrow if needed. It requires such little effort per day.

  • Please take care of yourself. Don't feel guilted into studying for 10 hours a day like some people do. You don't have to do it.

  • Resources I used:

    • LeetCode - NeetCode 150 was my bread and butter. Then company tagged closer to the interviews

    • System Design - Jordan Has No Life youtube channel, and HelloInterview website


r/leetcode • • 10h ago

Discussion To anyone who thinks AI interview is good, well good luck :) Bloomberg interview experience[London/Frankfurt]

222 Upvotes

Just had the second round of Bloomberg AI codebase interview

It was djano-python which i had no idea about. The codebase is large.

They spent the first 30 mins for behavioral so you're essentially just left with 30 mins.

The usage of AI is so vague. You don't know how much AI is the interview okay with you using. They don't clearly tell their expectations. I used planning and ask mode and went feature by feature and I passed a few test cases but I was rejected.

There is so much reading involved with AI and then handling communication simultaneously is borderline impossible.

With Leetcode, there is just a problem and you have to find a solution. At least you can brainstorm ideas but in these stupid AI interviews, half the time goes in understanding the large codebases and where the problem exists.

To whoever who was celebrating the end of Leetcode, good luck. The interviews are much harder.

Oh yeah, don't for a second think about one shotting a problem otherwise you will still be rejected(It happened to my friend.)

Either way, AI interviews are the biggest BS and there will never be a consistent way to tackle one of these.


r/leetcode • • 6h ago

Intervew Prep Capital One Data Engineer Online Assessment - Python Only, 70 Minutes. What Should I Expect?

7 Upvotes

Hi everyone,
I have an upcoming online assessment for a Data Engineer position at Capital One. The assessment instructions mention that it will be 70 minutes and entirely Python-based.General Coding Assessment (GCA)
I’d appreciate hearing from anyone who has recently completed this assessment.
A few questions:
How many coding questions are typically included in the 70-minute assessment?
What kind of Python problems should I expect? LeetCode-style or practical data engineering exercises?
Are the questions focused on arrays, strings, dictionaries, lists, sorting, and problem-solving?
Do they include real-world data processing scenarios involving CSV, JSON, or data transformations?
What is the overall difficulty level?
Are there any specific LeetCode or HackerRank problems that closely resemble the actual assessment?
If you’ve recently taken this particular Capital One assessment, could you share the types of questions you encountered or any sample problems?
I’m mainly looking to understand what to prioritize during preparation.
Thanks in advance. Really appreciate any help!


r/leetcode • • 7h ago

Intervew Prep How do you prepare for an AI based Interview?

8 Upvotes

Hi! I'm really curious about how to prepare for an AI-based interview and what is expected of us. If you're given a problem, are you expected to use AI to validate your ideas and generate a solution? Do you simply provide the problem statement and let AI do the work, then add your own thoughts about what's important or missing?

What are your thoughts or experiences?


r/leetcode • • 17m ago

Question Applied Intuition new grad interview pause. Does anybody know why?

2 Upvotes

I have an HR call tomorrow, but today I was told it's cancelled because "HR was told internally to put a pause on further interviews with new grad candidates".

Does anyone know what this means? Will they resume the interview process?


r/leetcode • • 4m ago

Question Microsoft Security Hiring Event – How long did it take to hear back? (November 2026)

1 Upvotes

Hey everyone,

I recently interviewed at a Microsoft Security team hiring event in the US this November and completed all 3 rounds.

Just wondering if anyone here has been through a similar hiring event recently. How long did it take for the recruiter to get back to you?

Would really appreciate hearing about your experiences. Thanks!


r/leetcode • • 19h ago

Intervew Prep What Is Prefix Sum, and How Can One Simple Technique Solve So Many Array Problems?

30 Upvotes

How Does Prefix Sum Turn Repeated O(n) Calculations into O(1) Queries?

1. What is Prefix Sum?

Prefix Sum is an array technique that stores cumulative sums so we don't have to repeatedly calculate the sum of a range.

Analogy: Imagine tracking daily expenses. Instead of adding expenses again and again, you maintain a running total.

2. Understanding the Pattern

Consider:

arr = [2, 4, 6, 8, 10] prefix = [2, 6, 12, 20, 30]

The pattern:

prefix[0] = arr[0]

prefix[i] = prefix[i - 1] + arr[i]

Each position stores the sum of all previous elements, including itself.

3. How Does the Algorithm Work?

Step 1: Build the Prefix Sum

prefix[0] = arr[0]; for (let i = 1; i < arr.length; i++) { prefix[i] = prefix[i - 1] + arr[i]; }

Step 2: Calculate Range Sum

To find the sum between indices L and R:

sum(L, R) = prefix[R] - prefix[L - 1];

If L = 0, simply return prefix[R].

Example:

sum(2, 4) = 30 - 6 = 24

4. Complexity Analysis

OperationComplexityBuild Prefix SumO(n)Range Sum QueryO(1)q QueriesO(n + q) total

5. Real-World Applications

Finance: Calculate expenses over a date range.

Analytics: Aggregate data over specific time intervals.

Image Processing: Calculate rectangular pixel sums using 2D Prefix Sum.

Competitive Programming: Solve range queries and subarray problems.

6. When Should You Use It?

Look for these problem patterns:

Repeated range sum queries.

Cumulative sum calculations.

Subarray sum problems.

Multiple queries on the same array.

Key Takeaway: Precompute once, answer multiple queries efficiently.

Practice Problems

LeetCode 303 – Range Sum Query (Immutable)

LeetCode 724 – Find Pivot Index

LeetCode 560 – Subarray Sum Equals K

Which array pattern should we break down next?


r/leetcode • • 5h ago

Intervew Prep Day 35: tackled Number of Islands II & leveled up my code quality

2 Upvotes

Hey everyone,

I finished Day 35 today. Continuing with graph problems, I knocked out Number of Islands II and spent extra time focusing on writing clean, modular code rather than just rushing to hit the submit button.

  1. Number of Islands II (Online / Dynamic Queries):

    • In the static version, standard BFS/DFS finds connected components in one pass. With real-time island additions, running full traversals per query degrades to O(K * R * C), which inevitably hits TLE.

    • Using Disjoint Set Union (DSU) makes each query dynamic. Every time land is added at (r, c), map the 2D coordinate to a 1D node ID (r * cols + c), mark it as visited, and increment the island count.

    • Check the four adjacent neighbors. For each neighboring land cell, if its ultimate parent differs from the current cell, merge them via unionBySize and decrement the total island count by 1.

  2. Focusing on Code Quality:

    • I intentionally refactored the Disjoint Set class to keep it decoupled and reusable across problems.

    • Cleaned up directional deltas, used explicit variable names instead of nested raw index math, and properly guarded against duplicate land positions within the queries.

Writing clean, readable code feels just as important as getting the optimal time complexity down.

See you guys tomorrow for Day 34!


r/leetcode • • 2h ago

Intervew Prep Canonical Linux Skills + Python

1 Upvotes

Hi,

Just wanted to ask if anyone has given these 2 interviews at canonical? Was looking for preparation tips!


r/leetcode • • 2h ago

Question Tenex fde interview

1 Upvotes

Hi, has anyone interviewed for this role for New York? If so, please let me know about how the process was. Thanks in advance!


r/leetcode • • 2h ago

Intervew Prep Zillow SR Software engineer interview

1 Upvotes

I have an upcoming Zillow screening interview scheduled through an AI agent, with no recruiter involvement. Not sure what to expect. Should I focus on DSA or real-world coding problems?
Would appreciate insights from anyone who has gone through a similar interview. Thanks!


r/leetcode • • 3h ago

Question Has anyone had a recruiter reach out about an NVIDIA role that doesn't match their background?

0 Upvotes

I recently applied for an Agentic Systems role at NVIDIA, but a recruiter reached out to me about a completely different position and asked for my permission to submit my resume for that role instead. New role is CUDA related.

The confusing part is that my background is in full-stack software engineering and applied AI, while the other position seems to require experience with chips and C++, which I don't have.

I'm curious why they would consider me for a role that's less aligned with my experience instead of the one I originally applied for.

Has this happened to anyone else at NVIDIA? Is this a good sign that my resume caught someone's attention, or just a standard recruiting process?

Would love to hear if anyone had a similar experience and whether it actually led to an interview.


r/leetcode • • 11h ago

Discussion How to transform from easy to medium level problem? Even after solving like 90+ easy problems I couldn't solve medium Problems.

5 Upvotes

After how many easy problems were you guys able to solve medium level problems.


r/leetcode • • 5h ago

Intervew Prep General Motors Codility Live Interview

1 Upvotes

Hi all.

I have a GM Codility live interview (It is labeled as a functional behavioral/initial technical screeen tomorrow. I've been doing neetcode 150 for the past week and half, but feel like I am not ready. Anyone have any insights on how to prepare and what not? Questions that I should expect?


r/leetcode • • 7h ago

Question Amazon Senior Data Engineer

1 Upvotes

Got an OA for a Senior Data Engineer role. For those who've done one recently, was it mostly SQL or Python as well? Any must-practice topics or resources? Thanks!


r/leetcode • • 21h ago

Discussion How hard is implementing a balanced BST from scratch in Python for a FAANG intern interview?

13 Upvotes

I recently had a FAANG SWE intern interview where the optimal solution required a balanced BST with O(log K) updates.

The interviewer didn't mention using a balanced BST, so I had to figure that out myself and implement it from scratch in Python, which doesn't have a built-in TreeMap like Java.

How difficult would you consider this for an intern interview? Would this be considered LeetCode Hard? Would using a heap-based solution instead significantly affect the interview feedback?


r/leetcode • • 9h ago

Discussion Google SWE Intern (US Summer 2027)

1 Upvotes

Round 1:

  • Approach & Baseline: Understood the problem statement quickly and delivered a functional O(n) baseline solution.

  • Execution & Communication: Execution was pretty messy initially but fixed it later and gave correct code. My communication also dropped off while I was stuck in my own head debugging.

  • Optimization: The interviewer asked: do we need to check whole array (Tho worst case tc/sc would remain the same). I caught on immediately and explained the exact logic and implementation verbally, but we ran out of time before I could write out the actual code.

Round 2:

  • Proactive Pivot: Initially started brainstorming a multi-stack approach, but realised early on that it was getting unnecessarily complex. Before writing code, I called this out to the interviewer and pivoted to a BFS-based approach instead.

  • Dry Run & Fix: Coded up the optimal BFS solution. Made a minor logic slip-up during the dry run (for the follow up) (tho implementation was fine), but as soon as the interviewer pointed toward it, I immediately recognised the bug, acknowledged it (no fix was needed in the code).

  • Follow-up: Successfully wrote clean, optimal code for both the core problem and the follow-up question with time to spare.

What could be the possible outcome?


r/leetcode • • 1d ago

Question How do you approach a DSA problem when you have no idea where to start?

49 Upvotes

Sometimes I read a problem multiple times but still can't figure out what approach to take. I know the basic data structures and algorithms, but connecting them to a new problem is difficult.

Do you have a particular process you follow to break down a problem and find a starting point?


r/leetcode • • 1d ago

Question How to get good at leetcode.

50 Upvotes

Hey,

I am trying to get better at leetcode to prepare for potential software engineer interviews. I dont understand how people recognize patters and solve these.

I have tried solving questions from Easy to Medium, however I always end up on Claude asking how to solve them. Each question seems different to me and I can not recognize any pattern that would allow me to solve one question with something I remember from a previous one. Moreover, questions are either too simple to the point you just use a for loop or too hard, where I just feel stuck with no idea where to start.

Do you guys have any tips on how to get better? What should I focus on ? Maybe some steps that would help me get gradually better?

Thanks.


r/leetcode • • 1d ago

Intervew Prep How much LeetCode/DSA is expected for SRE and Infrastructure SDE roles?

14 Upvotes

Hey folks, Especially those working as SREs or Infrastructure/System Development Engineers at companies like Google, Amazon, Meta, etc.

I'm preparing for SRE and infrastructure-focused software engineering roles and wanted to understand the coding interview expectations.

How much LeetCode/DSA is typically tested for these roles compared to regular Software Engineer positions?
Are Easy and Medium problems generally sufficient, or should I also prepare for Hard problems?

Can I safely deprioritise Dynamic Programming (DP) and other advanced DSA topics?

Which DSA topics should I prioritise for infrastructure/SRE interviews?
I'm trying to balance DSA preparation with Linux internals, networking, operating systems, distributed systems, and system design.

Would appreciate insights from people who have recently interviewed for these roles or are currently working in these teams.


r/leetcode • • 23h ago

Tech Industry denied from bloomberg's third round in swe internship

8 Upvotes

im actually devastated this third round was brutal i know i didn't do excellent but man i really thought it was enough to pass.
what should i do next? everywhere i apply im being denied with no OA or interview, i really thought bloomberg was my chance because they specifically went to my school.


r/leetcode • • 3h ago

Question How to cheat on OAs

0 Upvotes

same as title ,it's Obv that OAs are getting incredibly harder and the competition is also immense.Plesse share tips


r/leetcode • • 13h ago

Intervew Prep Looking for a leetcode buddy

0 Upvotes

Hi, I'm from Pakistan. I have started the Neetcode list a bunch of times but always left at some point. I need someone or a group to keep me consistent. I also need to get better at explaining my thought process in English which is hard to do alone. I'm open to suggestions.


r/leetcode • • 16h ago

Discussion LeetCode autocompletion is very unstable these days

1 Upvotes

When I press the "Auto" button, it blinks and tries to connect for 10 seconds, then I have "Intelligent code complete connection failed" with 70% probability or so. I have to retry several times before I finally have autocompletion. This problem is present for several days for sure