Hi folks, hope you're doing well!

I’ve been putting together some notes from my recent interview experiences, and I figured they might help anyone preparing for their next big round.

I’d post this on LinkedIn too… but let’s be honest — if my current company sees me dropping interview prep notes, they might start polishing my exit pass. 😄

(They think I’m in the top 0.1%, so let’s keep their illusions intact.)

Anyway, here are a few things I’ve learned the hard way:

🔥 Even easy DSA becomes WWE SmackDown when the interviewer is staring at you.

🔥 Review your basics — JS Promises, Python decorators, SQL joins, event loops — the classics never die.

🔥 Practice talking through your thought process; silence is not golden in interviews.

🔥 Don’t underestimate HR rounds — they can ask technical questions when you least expect them.

Interview tracker summary

Company Role Application Method Interview Date (Approx.) Status Key Takeaways & Notes Questions
Oracle Java Backend Developer Recruiter Outreach (LinkedIn) November 6 Rejected Strong round covering System Design, DSA, Core Java, and a pair-coding challenge. Performance felt solid; awaiting feedback after clearing the first round. Create a Caching System where we will have 2 method one to add the log into the cache and other we have to get the data of last 5 mins.
Rippling Frontend Engineer Company Careers Portal November 6 Rejected Fell short in the initial routing/technical round. Need to sharpen core JavaScript fundamentals — especially Promises, async flow, event loop, and improve hands-on React.js problem-solving. Solved ~90% of the problem. Was given with a Promises implemented have to read the promise response and then set the data on the screen and list the color and display it dynamically. React.js and Javascript
NxtWave Full Stack Developer Naukri Upcoming Active / Lined Up Cleared the OA (medium/hard DSA) + AI-based Interview. Next round will focus on DSA, React.js, and Node.js, based on the job description. Got the email for next round filled the form but no update they are reaching me for the other roles. LOL AI based interview question about resume and React.js and Node.js
Decentro SDE (Backend Focus) Wellfound Recently Concluded Rejected Cleared OA (DSA + SQL) and a Bar Raiser round focused on Backend Concepts, Python Coding, Python Internals, OOP. Missed a technical question in the final quick chat: **Python Decorators (specifically using *args and kwargs inside a wrapper function), leading to rejection. Exact Code which I was unable to code full - **# Function doing sum of 2 numbers# Create a decorator (Caching layer)def caching(func):cache = {}def wrapper(*args,**kargs):key = (args)if key in cache:print("From Cache Sum : ", cache[key])return cache[key]response = func(*args,kargs)cache[key] = responsereturn responsereturn wrapper@cachingdef add(*nums):sum_value = sum(nums)print("Sum : ", sum_value)return sum_valueprint(add(2,3))print(add(1,5,5,6))print(add(2,3)) Grilled on Python Concepts, OOPS, ACID, Generators, Wrappers, DSA need to implementation all the permutation of a list.
SmallCase Backend Engineer LinkedIn Easy Apply Recently Concluded Rejected Cleared OA (DSA ) and a Interview round focused on Backend Concepts, Microservices, Kafka, AWS, DSA. The interview was good hoping for the best. I think got rejected as I was unable to answer the Generator in python and Wrapper properly. Need to cover the python basics properly. Discussed about resume, how i have implemented custom message queue using the DB, talked about microservices and question regrading python(Generators)
NAB Platform Engineer (SDE 1) Direct Reached Interviewed Rejected Scored 67% on online Codility test got 3 question 1. Fix the smallest number < s having the maximum sum of digit. 2. Fix the code its is something based on ceil(a+b // 4) 3. In based on Prefix and Suffix type question “I have passed the Round and they called me for the interview on 13th Dec but I am travelling home on 10th So asked them to go Virtually but I am sure they will skip me SAD 😢” New update that I have interviewed them Online ace the Round 1 explain the DSA problem properly. Round 2 I have 2 sum kind of problem and I wrote the code but the interviewer wan’t why the code work and why his code which he pasted doesn’t work He was not satisfied with my answer it seems. Asked the recruiter for the status She told they are not moving further. Tired of getting rejected. Waiting for rejection mail. Just learn to prepare for different scenario. The Recruiter it watching and we are 2 on zoom call solving the problem they will choose the best score person between 2.
Swiggy SDE - 1 Applied on Company Portal Interviewed Interview the first round and just messed off (Will surely get Rejected) The interview start with a bald yawning and rude. He directly jumped into pasting the question.The Question was related to declicious food list of food where you have to find the sum of two food where the sum is the power of 2. I read the question and got panicked. In that case I need to be calm and read the question properly. I told that I will use 2 loop to just create the pair and find the it is power or not and number of pair. He asked me how you will do power and I just answer we can use Math.pow or bit shift operation for this but he just rudely said how can you do that. I got overwhelmend and just messed the approach. And then I was asked to optimized it till that I was blank and my mind went outside. I just explained him nonsense. I wrote code which was giving wrong output. Wrote something. Later asked about Java what is JVM, Memory Leak, IOC Container, Forgot the full form of IOC, Dependency Injection. Waiting for rejection mail. How dumb I am I could have store all the 2 powers value till 20 which was the max and then use two sum approach and solved it. I am doubting my knowledge now.
Nike SDE - 2 Applied on Company Portal Interviewed Rejected There were 2 Round in Office. Asked questions related to system design, resume, the asked about sql query and about design pattern → I don’t know where the Circuit Breaker pattern comes in. Talked about a SQL query and have and point that there is a concept of OFFSET but he wanted me to use nested query. Round 2 - It was also based on resume asked me a dsa question to give all the palindrome subarrays. I solved it with the recursion and brute force but he wanted me to optimize it where I lost, asked about kafka e 2 e working and I just told consumer and subscriber which he was not happy about and while going on I told that I have used kafka’s this part and he was not happy about and in last review mentioned that I have to know everything from the basic. Which I do agree. Had a learning. Need to Learn everything from the scratch and question can be from anywhere and any type/form. We really need to prepare for everything.
Microsoft SDE - 1 Applied on Company Portal Interviewed No Sure May be 50-60% chances depend on the other candidates. Manifesting of getting another chance 🤞. Rejected got a call with Recruiter and he told that my second round didn’t went well I had Round 1 (DSA) where I solved the first problem using recursion with memoization, but I forgot to add visited tracking failed one test case. Due to internet fluctuations and limited time, the interviewer said he understood my intuition and moved on to the next question.The second question was Stock Buy and Sell. I explained that I would use a greedy approach: buy at a lower price, sell at a higher price, keep track of the minimum price so far, and update the maximum profit accordingly. When the current value is greater than the minimum price, I sell, add the profit to the answer, and update the minimum price. This approach runs in O(n) time. The interviewer seemed satisfied and, during feedback, advised me not to overcomplicate the solution but to think simply and break the problem into smaller parts.In Round 2 (System Design), I was asked to design a cache similar to an LFU cache. Initially, I got confused with LRU, but after asking clarifying questions, I understood the problem. The interviewer then asked me to design it with O(1) time complexity for all operations. I could not immediately derive the full O(1) solution and proposed a single doubly linked list with a hash map, which would require O(n) time for some operations. Due to internet issues and very limited time, I implemented only the get operation. The interviewer seemed satisfied with my approach, and afterward explained that the optimal solution would use two linked lists along with a hash map to achieve O(1) operations. Need to learn System Design based DSA need to focus more on Hard > Medium > Easy.
ZZAZZ SDE-1 Recruiter Reached through LinkedIn Interviewed Will be Rejected/Ghost. The Interview was bad. I couldn’t ans the basic of JS,React.js and can’t solve the flattened array problem. I am literally pissed off with all the things what is going with me. I have to restart everything properly.
GLACIS Founding Engineer Wellfound Interviewed Rejected The Interviewer was from Vietnam. Its very difficult to understand his accent. Was asked question related to Networking like the OSI layer, OSI vs TCP/IP
Autodesk Full Stack Engineer Naukri Interviewed The interview as good just missed the Optional and Stream.Hoping for the next Round. Got Rejected as unable to ans 2 simple Java question of Optional and Stream it really hurts The interview went very well, and I genuinely enjoyed the questions. I implemented a singly linked list in Java, worked on database schema design, designed a high-level AWS architecture for image compression, and answered questions on core Java, design patterns, and Spring Boot. We also discussed REST API design and best practices. Overall, it was a great experience and I gave my best; the only minor gaps were around Java 8 Optional and Streams. Need to brush up my Java concept more properly
Akamai SDE 2 Naukri Interviewed Offer Received OA → Received OA on 13 Jan completed till 14 Jan Don’t remember the exact questions. But there are 2 DSA and also SQL based questions. R1 → (Nitu Rathore [Sr. SDE], Anand Subramanian [Sr. SDE]) (3rd Feb 2026) Asked about Java Filters, Basics and all this things. There were questions from Spring Boot. The DB question are super difficult like they asked me how Postgre work how it different from MySQL which to use when ans more. There are questions from basics but twisted. R2 (Reached after 2 months approx.) → Mark Warren [Senior Engineering Manager], Phil Heller [Principal Network Systems Engineering Lead] (30 March 2026). It started with the team the tech stack the things they were doing. It was Platform team. Crazy tech stack like python linux and more. They I asked why python not c++/rust as python have bottleneck and speed issues. They ans as the team competency on the tech not choice .The interview went well covered my Linux, Networking and DB knowledge. The first question was what happen when we press click start on the Linux machine. Explained full booting process and all. Then asked about how the request flow in dept when we do www.google.com to a linux server. Explained all the steps covered DNS,Routing,Discovery,Server,IP,MAC Address and all. Next asked about MySQL vs Postgres and then asked about the Migration and how it work there is a difference in both DB. I missed the Postgre feature but he was very cool he told he got the ans what he wanted. Then we move over to SQL it was easy join but I added something extra to the query as my advance understanding he told it was not need as we can remove the ISNULL so we don’t need that but with that also it will work it run all the testcases. They seems to be happy. As time was getting over they lastly asked about validation on ipv4 with regex I smiled and told about I am not that good in regex they smiled and told we don’t expect that we need all the things to be known by everyone. Still I try and told let me try. I try to explain the approach. Then he asked me about /d* /d? /d^ I answered that and he was happy. We tacked about bit about GENAI and more. Then he was curios about how I learned all this I told the truth about the Rahul Maheswari who was a google engineer teaching us. They were so happy about it. Then Phil asked me to explain about what AI research and open source project I am doing I explained about Omem then he asked did you use LLM for code I told the python script were written by me but I am shifting from python to rust so using llm for that. He told he will take a good look on the project. He was on my github and checking things. I was amazed and loved it. The between talk about for R2 I have waited almost 2 months and he assured me that this result will be faster as there were some issue related to hiring. Need to clear all my basics
Myntra SDE 2 Naukri Interviewed No chance The interview was about LLD on the Car Rental System. I did all this things but he wanted class digram I explain the class digram properly but he told the class diagram should be proper from controller and all this stuffs. At last I didn’t get time to code full system.
ConverzAI SDE LinkedIn Interviewed Rejected R1 DSA round went well and got a takeaway assignment. R2 DSA round Got a graph problem similar exactly https://leetcode.com/problems/cheapest-flights-within-k-stops/description/?envType=problem-list-v2&envId=shortest-path Some behavioural. Interviewer told get ready for R3. R3 done was asked questions related to resume/behavioural/LP one DSA question which I didn’t find in leetcode it’s based on LRU. R4 - was great speaking to the Bhavik first interview on Friday we just speak basically like the Mentor and mentee we have to move the interview to Saturday. On Saturday given question I confused my understanding and was solving in different way but later solved it. It is basically Dutch National Flag problem the we modify it to sort the 4 char was fun. He advice me to think the problem first in simple way not to jump into the most difficult one. R5 → The CEO asked about the most difficult or tech you have solved or build that you are proud of. Given a question about I think Estimation planning. Suppose you have a building and you have to put elevator on it and peak hour there are 100 people at one time they can’t wait more then 2 minutes. You have elevator of capacity 40 person/elevator and can go from 0 - 50 in 1sec and then move from 50 - 100 in 2sec/floor. How many min no. of elevator we need I told with some cal first 4 but later recalculated and told around 9. But what if all the passanger take 9 elevator at 8:00 and 8:01 → 100 passanger , 8:02 → 100 passanger , 8:03 → 100 passanger. We agreed upon if there is no constraint we can put 103 elevator to smooth run one for each for first case then 3 can take 100 each time next. Then he asked about why change job told about interest in ai take ownership and build something that effect people. He asked any other interview going on I told no. The he told bestluck and he will update to HR and they will contact me.
Motive SDE-2 Website Interviewed Rejected I have solved the DSA question and when asked to optimised I have done that too but I think my explanation and trying to solve with only the collection var defaultdict and not able to use .get() is the point to reject
Flipkart SDE-2 Naukri Interviewed Rejected. Messed the System Design Round. Appeared the Machine Coding round have to design a BNPL system. Done all this with proper working code and submitted waiting for the result.Selected On the MC Interview asked question about the MC design ,db choice, design patterns, code structure, dry run. Then gone through 1. String partition based question (Greedy,Hashmap,Sliding Window) https://leetcode.com/problems/partition-labels/description/?utm_source=chatgpt.com 2. Graph based https://leetcode.com/problems/number-of-provinces/?utm_source=chatgpt.com solved with DFS asked to optimize this explained union path find but it took long but explained didn’t code. Selected for Design Round.
Amazon SDE-2 Direct Reach/ Company Portal Interviewed Rejected.Messed the Design Round Strong DSA rounds.Strong Leadership Principles discussions.Near-hire performance overall. R1 - 1. Recursion problem (adapted to DP)
  1. Second DSA problem (priority queue likely)
  2. LP: "Time you faced challenge" R2 - Payment Gateway Core: Design BNPL/Payment Gateway for Appstore
  3. High-level architecture (Merchant → Payment Gateway → PSP)
  4. Idempotency: How ensure no duplicate payments? (You explained ✓)
  5. API design: createPayment(), retryPayment()
  6. API Gateway vs Payment Gateway distinction
  7. Merchant security flow (tokens, encryption)
  8. Walkthrough: createPayment() end-to-end (timing stumble)
  9. Scale: 10k TPS, consistency requirements R3 → LP → 1. STAR stories (Ownership, Deliver Results)
  10. AI discussion (your FICO fraud background)
  11. "Challenge without boss approval" R4 → LP + DSA 1. DSA: DP confusion → TC/SC recovery
  12. LP: Resilience, Ownership questions
  13. Your questions back (impressed him) | Design walkthrough lacked:Structured flowDeep scaling discussionTrade-off articulation | | Yahoo | SDE-2 | | Interviewed | Interview loop Completed on Friday 6th March. Then I called the Recruiter on Monday where I got they are having more 2 people interview and then will have debrief by this week and will update me. Rejected | The interview were not in sequence. First there is a Tech Screening round. Passed that moved to proper interview pipeline. R1 - System Design Round Asked about Yahoo Notification System Design walked with proper approach multiple back and forth question and also had some new requirements added we both enjoyed the discussion at last I can’t design the API and the scheduler he told its okay as he asked multiple question. R2 - Coding Round Had some LP questions. Jumped to Coding a CustomIterator with next() hasNext() and remove(). Have got multiple back and forth question and handled this and all cases properly with writing and giving the test cases as well. R4 - Cross Functional - Discussed on the LP and grilled on LP with Resume created and asked everything. Went well answered everything properly what I guess. R3 - Coding Round 2. Intro and LP questions at the start. Moved over to DSA which was Implement Trie the added autoSuggestion and how to improve autoSuggestion. Did very will with proper TC and SC he seems to be happy. HM Round - Basic Discussion on Intro. Asked about what is my major work I explained at high level but he wanted a exact work I talked about the performance improve what I did for my project and approach I have used with flow and improvements. But I forgot what tool we used for performance and latency testing but I told we have never used that in FICO we only use Kibana and just used Prometheus for 1 month for some startup project. Get deep about this only. What is the org structure we have how we work in fico. How we handle a major issue in production explained with a proper story. I think he satisfied from my ans. Just on the tools like Prometheus he asked did you ever used it and I told I used it for some personal project form 10-15 days and not habitutation. Wanted to be true. Ended with some question about the onprem and GCP migration what Yahoo Mail and backend which this team is working on and how the choose the language and system architecture. And added a point from my side every time had trade offs and on big org it comes like cost vs performance and tech and he was like exactly and happy. Ended his note with will let recruiter get back to you. Hiring Manger → | | | YipitData | SDE-2 L2 | | Interviewed | Offer Received | R1 and R2 are almost to same will grill on resume, check you networking, os and computer basic knowledge. R1. asked a Basic Easy level DSA question the basic discussion were tough though. R2 kinda same but one DSA question and one kinda System Design Question related to partition and chucking and more related to how efficiently store data and get the k most frequent element. R3 → Almost the same type of question from every concepts dsa solve on dsa problem (kind of dsa and system design used), thread, thread locking, how to scale, other basic deep level question. At last he told the interview was okay as I ask for suggestion. R4 (Discussion with the CTO of Edison Software) [(01/04 /2026)] → He stared about talking about the issue with the 90 Days Notice period. I assured him about the 30 Days I can join or max 45 Days. And assure about joining the team. He asked me about the things I know about. I explained then my basic understanding. Then he started explaining everything about the company YipitData and Edison Software. Their product where and what tech I can work on and what is the upside of the things Why YipitData acquired Edison Software their new products and shifting team from China to India due to new USA data policy. The he came to compensation as my base is 16.5 LPA and CTC as well + 1 Lakh Bonus and I have also got 1.5 Lakh around RSU 1 FICO stock. I said my expectation is around 50-60% from base He told I told Recruiter 25 Lakh he told we will try to come close many people from MAANG join us so we pay good and we will try but there is no RSU for this level L2 (SDE2) my experience is 3.2 years (2.8year full time + 6 months internship) so he saying 2.6 year experience and with in 12-18 months can jump to L3 having good RSU like 40 LPA. Today(02/04/2026) ANSR Neha Hegde reached me for sending all the documents and current company data. Not sure haven’t received the offer letter. | | | JPMC | SDE-3 | Company Portal | Interviewed | I called the interviewer as he was busy after sometime he called me back around 12 march @ 5:30. I ask for any update. He told that they want to keep me on hold as they are taking interview of other candidates too. No sure it is positive or negative or my interview went average. Rejected for R3 | The R1- The interviewer was awesome asked question about the architecture of the product I work on OM. Question about features of Java 8, question about Design Patterns, questions on check if a string is palindrome or not in java or python. I told I am comfortable in Python but she asked me to code in Java 😂. Solve this in optimal approach. Had good discussion. Completed the interview in 30 min. Had 1 hours don’t know why. Asked question about her how she jumped from service based to JPMC. AI fear and any advice on DSA,SD or Communication (she told nothing as per now). (12th March → 11 AM to 12 PM) The R2 was good I have ans the question asked started with the architecture about what is the GenAI tool I have created move over to multiple question on it like how or what I have done on it my contribution and then moved over to why not RAG why finetune as that as we are working on code generation and refactoring it is difficult to implement that with RAG right. Asked about the how finetuned and what is size we have used and like 10 Million and above Bits. Then move and asked to implement the reading the data from 2 file like one is the csv (Employee) one is json (Department) and then read it and get the max salary as per the department done the code moved to code the the pushing the data to sql and she is having doubts on the how to maintain the max salary explain properly. We moved to next question due to time like how would you improve this on production level explained about Availability, Scaling and all but she told before that we should handle the exception and told about we can get error while handling with files a IO or parsing told I forgot the jsonparsing expection in python but can do with java and she told okay explain the try catch with java and handle the parsing error and all. Then moved to the SQL question one table Sales -> employee_id, amount, date and get the Top 3 sales of each employee give code Select employee_id,amount,date from( select employee_id,amount,date,ROW_NUMBER() OVER ( PARTITION BY employee_id,DATE_TRUNC(‘month’,date) ORDER BY amount DESC ) AS rn FROM sales ) r where rn <= 3; but it will not work properly where the salary are same while. Then while trying to fix that she jumped over to next question as we have less time how would you handle if we are getting data in diff chuck like for the department right we get 10 dept once 20 dept next once 5 dept next how to handle this. I told we can use message queue like Kafka and push the data into the Kafka and process it through workers in case where we want to process in the sequence manner but when there is a time we want to run once we can modify the approach. Then I was trying to ans that and she told we should end the call as the time is over. No sure the reaction and any question for me. (12th March 2:15 - 3:15). R3 (F2F) 26th March → Start with what is your day to day worked. Jump over to basic fundamental Java Overloading and Overriding. Can static method override I told no. Why String are immutable I told due to multithreading and memory/space optimisation. Asked to create a Employee with 2 member id and name with the immutable mistakenly written final static later on after he pointed out I got it maid only final asked that can we add getter setter. I told only getter. asked final List<String> = new ArrayList() can we do .add(),.update(), I told no.The asked create new emp1 emp2 with same values and put to HashMap<Employee,String> add emp1 and emp2 and what will be the length I ans 2 as it will take different memory for the object. Then he asked about how to fix this I told we can check for the object compare on constructor.Create new method to compare. Then he told don’t java provide it automatically. I told we can use comparator. Asked about check palindrome in long string code it but mistaken time complexity to O(log n) then asked about synchronized block and ans like synchronized method like it will lock the full method and what it will locked asked I told I don’t know. The asked about atomic and I can’t explain it properly just wrote AtomicInteger. | | | AutoDesk | SDE 2 | Company Portal | | Rejected | R1- Intro, Question about sorting the employees ages → MergeSort implementation in Java, Some discussion on Java Concepts, HashSet can contain null values and how much number of, DB, ACID properties, SQL to get 3rd highest salary employee,API Gateway vs Service Discovery, Method Overloading vs Method Overriding, How you can add new method to a Abstract class without affecting its implementation class,Response Code (200,300,400,500), @Controller vs @RestController, AWS basic, Have you used Docker, Maven/Gradle,How to know which index a particular SQL will use by the query. Asked for suggestion/improvement said it was okay any feedback ask from HR. | No Sure why I got rejected. May best testcase/edge cases. The interview was good though. | | Swiggy | SDE 1 | Company Portal | | Rejected | R1 → Basic discussion on the Resume and past work. Jump over to DSA 1. LIS → DP 2. Longest subarray with K distinct sliding window + Hashmap approach it was awesome. He was very happy. R2 → System Design , Design the Notification System Jump over from HLD to LLD good back and forth question some ans I fumbled but the interviewer was awesome helped me. He told great design.Last when I asked any suggestion he told Try to frame and ask more question, show your thought/ thinking clearly and talked about know in and out of things you are using on the HLD part. R3 → Discussed about the resume work and FICO. They asked me to come down to office next Day. R4 (Onsite) → No code have brainstorming Rotten Oranges problem solve and given the approach with BFS then discussed about System Design, SQL, resume and work. All the interview was excellent chill. Loved It. Hope they give me a chance. | | | Walmart | SDE-3 | | | Interviewed | R1 → Interview started with question from my resume like TLS/SSL. Fundamental about which java version and which spring boot version we use I forgot about that.Then we moved to the DSA questions. First was https://leetcode.com/problems/search-in-rotated-sorted-array/Search in Rotated Sorted Array - LeetCodeCan you solve this real interview question? Search in Rotated Sorted Array - There is an integer array nums sorted in ascending order (with distinct values). Prior to being passed to your function... https://leetcode.com/problems/container-with-most-water/Container With Most Water - LeetCodeCan you solve this real interview question? Container With Most Water - You are given an integer array height of length n. There are n vertical lines drawn such that the two endpoints of the ith li... class Solution { public int maxArea(int[] height) { int left = 0; int right = height.length - 1; int maxArea = 0;  while (left < right) { int h = Math.min(height[left],height[right]); int width = right - left; maxArea = Math.max(maxArea, h * width);  if (height[left] < height[right]){ left++; } else { right--; }  }  return maxArea; }} https://leetcode.com/problems/merge-k-sorted-lists/description/ /**Definition for singly-linked list.public class ListNode { int val; ListNode next; ListNode() {} ListNode(int val) { this.val = val; } ListNode(int val, ListNode next) { this.val = val; this.next = next; }}/ class Solution {  // private ListNode mergeTwoLists(ListNode l1, ListNode l2){ // ListNode dummy = new ListNode(0); // ListNode curr = dummy;  // while (l1 != null && l2 != null){ // if (l1.val < l2.val){ // curr.next = l1; // l1 = l1.next; // }else{ // curr.next = l2; // l2 = l2.next; // } // curr = curr.next; // }  // curr.next = (l1 != null) ? l1 : l2; // return dummy.next; // }  // private ListNode merge(ListNode[] lists, int left, int right){ // if (left == right) return lists[left]; // int mid = (left + right) / 2; // ListNode l1 = merge(lists, left, mid); // ListNode l2 = merge(lists, mid + 1, right);  // return mergeTwoLists(l1,l2); // }  public ListNode mergeKLists(ListNode[] lists) { if (lists == null || lists.length == 0) return null;  PriorityQueue<ListNode> maxHeap = new PriorityQueue<>( (a,b) -> Integer.compare(b.val, a.val) );  for (ListNode node: lists){ if (node != null) { maxHeap.offer(node); } }  ListNode dummy = new ListNode(0); ListNode curr = dummy;  while (!maxHeap.isEmpty()){ ListNode largest = maxHeap.poll(); curr.next = largest; curr = curr.next;  if (largest.next != null) { maxHeap.offer(largest.next); } }  return dummy.next; }} R1 was good I have cleared the round. R2 (LLD & HLD 22nd April) → Started with resume grill. Then he switched to the project architecture discussion in depth. The we discuss about the question [Banking System] → Ans I gave HLD

Banking Application

Requirements

Functional Requirements

  1. Account Management -> Create account, View Balance
  2. Money Transfer -> Same Bank, Different Bank
  3. Transaction Details/History
  4. Notifications (SMS/Email)
  5. Authentication (login)

Non-Functional Requurements

  1. Consistency >> Availability (CAP)
  2. ACID properties
  3. High Availability
  4. Logging/Auditing (Banking Regulations)
  5. Latency (< 200ms for reads)

Services

  1. Account Service -> Manage accounts -> Balance queries

  2. Payment Service -> Initiates transfer -> Validates funds

  3. Ledger Service -> Source of Truth -> Stores all transactions -> Accounting

User

UserAccount user_id account_id

Accounts

account_id -> PK user_id -> now single account currency status created_at

Balance

balance_id -> PK account_id -> FK balance updated_at

Ledger

ledger_id -> PK transaction_id -> FK account_id -> FK amount entry_type created_at

A DEBIT -100 B CREDIT +100

CREATE TABLE accounts ( account_id UUID PRIMARY KEY, currency VARCHAR(10) NOT NULL, status VARCHAR(10) NOT NULL, created_at TIMESTAMP NOT NULL, user_id UUID )

Rest

users /transfer /accounts/{accountId}

Best coding practice ->

a -> b RestTemplate Autowired -> B -> PostCall

Timeout Retry ->

A -> B

Retry

Networkissue 5xx Rate Limiting Downstream Service

Not Retriable

Bussiness Failures 4xx Exception

Error handling Logging Circuit Breaker

Moved to R3 →

| |