DEV Community: OA VO Interview

Secure the Amazon SDE Offer with Confidence | Amazon VO Full Process Review + Subtle Tips for Success

OA VO Interview — Sat, 04 Oct 2025 13:11:04 +0000

This time, we share a more comprehensive Amazon VO interview experience, combined with Programhelp's assisted experience, showing how to successfully pass the interview through remote assists, real-time reminders, and strategic preparation. The characteristics of Amazon VO are that the interviewers' styles are very different, the difficulty of coding varies from easy to hard variants, and the BQ part is closely related to the Leadership Principles. However, through precise preparation and assistance, we can perform steadily in every round.

Amazon VO

VO1: 2 BQ + 1 Coding

BQ Title: Miss Deadline + Harsh Feedback
Coding: LRU Cache variants

The interviewer was a white guy, very friendly overall. The BQ part was very quick, the questions revolved around past project experience and how to deal with deadline pressure. Programhelp helped me to put together a specific case template and STAR framework in advance, so I answered the questions in a clear way, and I was able to explain the background of the problem, the actions, and the results quickly.

Moving on to the Coding stage, it was a variant question on LRU Cache. While I was writing the code, I discussed Runtime / Space with the interviewer, who was very friendly and even encouraged me to propose optimization solutions. I used Programhelp's training to practice LRU optimization techniques and boundary condition tests in advance, and successfully wrote the code and proposed optimization solutions within the limited time. Perfect! After that, it was over. The whole process was easy and efficient.

VO2: 1 BQ + 1 Coding

BQ Title: Dive Deep
Coding: Word Search II variant (Trie + DFS)

The interviewer in this round was an Indian, with a very cold style, staring at his cell phone almost the whole time without giving any feedback. BQ is a typical Dive Deep questioning method, asking me about the technical difficulties I encountered in the project and my thoughts on how to solve them. Although the interviewer didn't interact with me, Programhelp's real-time voice reminders are especially important at this stage, helping students clear their minds, avoid nervousness, and make sure that they describe the details of the project completely.

Coding is a variant of Word Search II, which requires Trie + DFS. After I wrote the basic solution, I found a bug and fixed it in time. The interviewer did not give me any positive feedback, and even gave me a sneer. Programhelp's assisted training will familiarize the students with Trie construction, DFS backtracking, and optimization techniques in advance, so that they will be able to hold their ground in logic and code even if the interviewer is not enthusiastic. Finally, the interviewer asked about runtime, and then it was over.

VO3: 1 BQ + 1 Coding

BQ Title: Outside your domain
Coding: Valid Parentheses

This round was with a white interviewer, very friendly and an alumni. He directly explained that his group is the recruiting group, and introduced the manager of the next day. BQ asked easy questions, mainly about project experience and some technical extensions. The coding question was very simple, it was Valid Parentheses. I finished it in a few minutes, and the interviewer gave me a bonus question, saying that it was not scored at all, and asked me to share my thoughts on it.

Programhelp familiarizes students with common basic questions and bonus questions in advance to ensure that they can respond efficiently to easy questions and show their highlights to impress the interviewer.

VO4: Pure BQ round

BQ Title: Miss Deadline + Outside your responsibility + Proud of project

In this round, the white manager was very friendly and helped me clarify some parts of my answer that were not clear, and encouraged me to talk about the part of the project that I was most proud of. Programhelp helps students in advance to sort out the Leadership Principle cases, highlights of the project, and strategies for coping with the difficult points, so as to ensure that the BQ answers are clear and focused. The whole process was like a relaxed conversation and went very smoothly.

Summaries & Student Success Testimonials

After the VO challenge, the student was able to secure an offer from Amazon SDE (New Grad), he concludes:

"During the VO process, I encountered interviewers with very different styles, from relaxed and friendly to cold and even disrespectful. However, with Programhelp's remote assistance, I was able to stay calm and organized to complete each question, whether coding or BQ, without panicking. In particular, the real-time voice reminders helped me to quickly clarify my thoughts and ensure that my answers were complete. In the end, I was able to get the offer without any problems and my confidence has increased greatly."

Lessons learned:

Coding Assist.: Familiarize yourself with the question variants, optimization schemes, and boundary conditions to ensure that each round is completed efficiently.
BQ Assists: Organize the STAR framework and Leadership Principle examples ahead of time in a well-organized and focused manner.
Stabilization of the state of mind: Keep the logic clear and steady, regardless of the interviewer's style.

With Programhelp's assistance, students were able to maximize their strengths, avoid getting stuck, and secure the Amazon SDE offer.

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Google Four-Round Interview Experience: Rejected!

OA VO Interview — Fri, 22 Aug 2025 08:08:46 +0000

Google's Technical Interview Preferences

Google's hiring criteria consist of four standards. The first is Role-Related Knowledge: as the name suggests, this refers to your professional competence in the position you are interviewing for. The second is General Cognitive Abilities. Since Google requires employees to be capable of handling any task at any time, this assesses foundational problem-solving thinking and logical reasoning skills, similar to the hypothetical questions used in McKinsey interviews. The third is Leadership Skills. As the name suggests, this refers to leadership and teamwork. The last is Googleyness. This assesses your alignment with Google's values and your ability to continuously adapt to changing circumstances.

Phone Interview

In an x-y plane, given the coordinates of routers in a network and the maximum distance range d for data packets sent by routers, determine whether it is possible to send a message from the source router to the target router.

As a follow-up question, I was asked to write code to handle the scenario where each router can only send packets to the nearest router, rather than to all routers within the range.

I used breadth-first search (BFS) to solve this problem and made some modifications to the BFS code in the follow-up question.

Interview Process

Round 1: Technical Interview
Q: Design a restaurant waiting list system that supports users of different sizes and has the following three functions:

Users can join the waiting list at any time

Users can leave the waiting list at any time

Users must be seated at a table that can accommodate at least their group size, with table size passed as a parameter

This is an open-ended question, and the input structure and design must be discussed with the interviewer to clarify specific requirements. Each group must be seated at a table that can accommodate their maximum group size.

Follow-up: How to test these functions.

I provided an O(logn) heap solution, which the interviewer seemed satisfied with.

Round 2: Technical interview
Q: K constraint

Sliding Window: Maintain a window ensuring the number of 0s or 1s within the window does not exceed k, dynamically adjusting the window's starting point to meet the constraint. The optimal time complexity should be O(n).

The start pointer indicates the starting point of the sliding window, and i is the current endpoint of the window. Since start and i only move to the right, the overall time complexity is O(n). After adjusting the starting point to satisfy the constraint, all substrings ending at i within the window meet the condition, so the result accumulates i - start + 1.

Follow-up: Optimized to O(n)

Round 3: Technical Interview
Q: Range Product Queries of Powers

For this problem, I utilized knowledge related to prefix sums. First, analyze the problem: we need to calculate the minimum number of powers of two such that the sum of these powers equals n. We can use a greedy algorithm starting from the maximum value, which is the power of two not exceeding n. Then, halve it and reduce n. After calculating the powers of two, sort them in ascending order, then calculate the prefix sum (this should be the prefix product), store it in an array, and use this array to calculate the query's answer.

Round 4: Googleyness
The questions I was asked:

Please describe a project you participated in that lacked clear goals and requirements

How to handle multiple projects

How to prioritize work tasks

A project that did not proceed as planned, and the measures you took to ensure similar errors do not occur again

Here, I primarily used the STAR method and combined it with Google's values to answer. Pay attention to the details in your description, as the interviewer may ask follow-up questions.

Interview Summary & Suggestions

I believe I performed exceptionally well in Technical On-Site Tests 1 and 2 and the Googleyness section (including follow-up), but I was unable to write the correct code in On-Site Test 3. The recruiter did not provide any detailed feedback on my individual rounds even after two requests, and stated that my performance in the first and fourth rounds was poor—this was somewhat surprising to me, as I felt both rounds went well. Additionally, my performance in the third round was quite poor, so I am unsure why I received positive feedback.

As long as you prepare thoroughly, the interview will be manageable. If you encounter any difficulties or need assistance, feel free to seek solutions here.

Meta E4 Software Engineer Interview Experience: I was rejected!

OA VO Interview — Thu, 21 Aug 2025 10:09:14 +0000

Hello everyone, I would like to share my experience of interviewing for the Meta E4 Software Engineer (Infrastructure Team) position in the US. Unfortunately, after so much effort, I was rejected, and I feel very discouraged and exhausted.

Background and Preparation

I passed the phone screening (primarily reviewing the top 100 Meta interview questions). I used Hello Interview for intensive preparation on system design. I also participated in mentor-guided courses and conducted mock interviews. For this position, I studied from morning to night, truly giving it my all.

Interview Process

*Round 1: Coding *
Q: Alphabetical combinations of phone numbers

The core idea of this question is to use recursion, or backtracking. First, determine the edge case: whether the string length is 0. When constructing the recursion, you need to define the boundary conditions for when to exit the recursion. The local condition is that the recursion should exit when the number of recursions equals the array length. For non-boundary cases, iterate through the first path, then consider the nth and n+1th paths based on the first one.

Essentially, this is the idea of mathematical induction: start from the 0th, then find the nth, and then find the n+1th. The idea here is to construct n strings, first enumerate the first one, and then gradually enumerate the n-1th ones. Whether it's recursion or backtracking, more practice is needed.

Round 2: System Design
Q: Distributed Counter

This question has the following key points. Storage: What should the schema for Redis caching look like? Besides Redis in-memory caching, do we need other types of storage? Does Redis need to be distributed storage?

Data Processing: Streaming data processing or batch data processing. What are the advantages and disadvantages of each? What are the differences between their respective frameworks? Read Flow: How can we support high read traffic while maintaining high write traffic? If reading data from Redis, how can we ensure the real-time nature of the data in Redis, and what are the trade-offs?

Round 3: Coding
Q: Building With an Ocean View

The approach for this question is straightforward: if there is no taller building to the right of each house, then it can see the ocean. We need to find the submax to the right, so we move from right to left, find the current max, and if the current h is greater than max, then it can see the ocean, and we record the current h as the new max. We can skip the sort function and directly use res[::-1]. [::-1] is a slicing operation, where:

-1 indicates a step size of -1, meaning it iterates from the last element to the first element of the list, taking all elements in reverse order. Therefore, res[::-1] creates a new list where the elements are in reverse order compared to res.

Round 4: Behavioral
The questions I was asked:

Q1: At work, what do you do when you disagree with a colleague?

Q2: Have you ever exceeded task requirements?

Q3: Have your suggestions ever been adopted by others?

I answered all behavioral questions well. The interview ended 10 minutes early. I felt the interviewers were quite satisfied. After this round, I was confident, but the subsequent results were a major blow.

Interview Summary & Suggestions

I really don't know where I went wrong. Maybe it was a small mistake in the programming section? Maybe it was the missing part in the system design? I don't think these mistakes should have led to rejection, especially since I had already corrected them. I'm very disappointed because I prepared for a long time. This was a crucial opportunity for me. Has anyone else experienced a similar situation? What should I do next?

If you've also faced difficulties and challenges in interviews, feel free to come here to find solutions!

Amazon Interview Experience: Rejected After Four Rounds of Interviews!

OA VO Interview — Wed, 20 Aug 2025 08:49:47 +0000

Background

I would like to share my Amazon interview experience with everyone to help others who are preparing for Amazon interviews. I went through multiple rounds of interviews and was ultimately rejected in the fourth round, which came as a surprise to me, as I had put in a lot of effort preparing for the interviews. I submitted my job application in November 2024 and received an online assessment on January 6, 2025.

OA

The assessment format is similar to Amazon's standard OA, including two data structure and algorithm (DSA) questions (medium to difficult). I successfully optimized and solved the two DSA questions and completed the behavioral interview section. I passed the OA smoothly.

The Interview Process

Round 1：DSA
Q1: Subarrays with sum equal to k
Given an integer array nums and an integer k, count and return the number of subarrays in the array whose sum is equal to k. A subarray is a contiguous non-empty sequence of elements in the array.

My approach is to construct prefix sums during the iteration process. Initialize {0:1} and set the position corresponding to index=0 to 1. Use a dictionary to record the number of occurrences of each prefix sum. Calculate whether the value of cur_sum - k exists. Store the results of existing prefix sums and their frequencies in a hash dictionary, trading space for time.

Q2: Searching in a rotated sorted array, subsequent questions involve time complexity
Given an array where nums[0]..nums[k] and nums[k+1]...nums[n] are both in ascending order, and nums[n] < nums[0]. Given a target number, return the index in nums; if it does not exist, return -1

This is a special binary search problem that requires consideration of the sequence in which nums[mid] is located. I have divided it into two cases for discussion: the first case is an ascending sequence, and the second case is two ascending sequences.

Round 2：DSA
Q1: Minimum Descending Path Sum
From the top-left corner to the bottom-right corner of an m × n grid, find the path with the minimum sum. Each move can only be one step to the right or one step down.

My approach is to use dynamic programming (DP). Initialize the value at the top-left corner. For each cell, the minimum path sum is the minimum of the sum of the paths coming from above and from the left, plus the value of the current cell.

Q2: Rotten Oranges
This problem requires a queue. Add the coordinates of all rotten oranges to the queue, and process all rotten oranges in the queue every minute.

My approach is to iterate through the oranges on the map, record the number of fresh oranges (to verify if all have rotted), and push all rotten oranges into the queue. Use BFS to process all directions of oranges in the queue within one minute. If the number of fresh oranges is 0, return the time.

Note that you must first check if the orange is within the map before checking if it is rotten; doing it the other way around will cause an out-of-bounds error.

Round 3：Behavioral
The questions I was asked:

Q1: Describe a time when a project you were responsible for received criticism.

Q2: A project you have analyzed and discussed in depth.

Q3: How did you solve the problem when data was unavailable?

The behavioral interview focused on LP (leadership principles). I learned about Amazon's leadership principles in advance and prepared corresponding stories, so I was very confident in my answers to the standard LP questions in Amazon's exam preparation materials.

Round 4：DSA
Q1: Nodes in a binary tree that are k units apart
Here, I used two methods: in-order traversal and double pointer search.

In-order traversal: Perform an in-order traversal on the BST to obtain an ordered list of node values.

Double pointer search: In the ordered list, use the double pointer method to find two numbers whose sum is K.

Q2: The nearest LCA in a binary tree

For this problem, I used a recursive approach. If the current node is null, return false directly. Recursively process the left and right subtrees using a postorder traversal, and determine whether the left and right subtrees contain nodes p or q. Determine whether the current node is p or q, and combine the return values of the left and right subtrees to determine whether the common ancestor has been found.

Interview Summary & Suggestions

I was very disappointed when I received the rejection email two days later. When I asked for feedback, they mentioned that I needed to improve my problem-solving skills. This feedback was difficult for me to accept because I thought I had answered all the questions well in all rounds. I was confident that I would pass the interview, but things did not go as planned. I don't know the real reason for the rejection, but I want to share this experience so that future interviewees can be prepared. If you encounter any difficulties or have any questions during the interview, feel free to come here to find solutions.

Google SWE L4 Interview Experience: Why Are Cultural Adaptability Tests Not Scheduled?

OA VO Interview — Tue, 19 Aug 2025 08:36:04 +0000

Background

LC：850+
YOE：4+
Education：MTech（IIT）

General Introduction

I completed all three rounds of DSA interviews, but the Google cultural fit test (Googliness round) was postponed multiple times (specifically the fourth time). Is this related to the feedback from the previous programming round (none of the rounds met the >= hiring standard)? Since this is a cumulative feedback system, the recruiters did not update the feedback after each round. I resolved all issues and follow-up questions, except for the first round where I was unable to complete the code for the follow-up questions, but I explained the approach clearly.

The Interview Process

Round 1: DSA
Q:Given a piano where you can only use one hand to play. You will place your hand on the piano and can play the five keys. In order to play a key which is not in range you will have to raise your hand. Find the minimum number of hand raises to play all the keys in given order.

Follow up: return the list of thumb positions you actually use—so you can see exactly where your thumb goes for each segment

Solved the initial problem with (2 approaches) optimal time & space complexity but could complete the follow-up coding. Although was in the right direction.

Interviewer was satisfied but told he wanted to get more out of me. Did communicated well with dry runs but unfortunately couldn't complete coding.

Round 2: DSA
Q: On my disk, I have a file system. The file system contains files which have a known size and directories that either contain files or directories. And I want to know, given any point in this file system, what's the total space it's consuming as I got a bit confused due to time running out.

Follow-up 1 : what happens when we need to add files?
Follow-up 2 : service is timing out on boot.

Was able to code optimally for the initial question and the first follow-up 1. There was no time left for Follow-up 2 but explained the approach verbally. Interviewer seem satisfied. Followed OOD for coding. Communicated well with dry runs.

Round 3: DSA
Q1:write an algorithm to find the top K most frequent words in a document. And I have to assume that the document is already parsed. So, I can read the document as an array of strings. For example, there is a set of words in the document array. So, Google, Bike, Pencil, Google, Bike, Google. So, the top two frequent words are Google and Bike.

Follow-up 1: What would you do if your document, not the words document, was not an array of strings, but it was actually a stream?
Follow-up 2: what happens now if your integer k is 0?

Q2: write an algorithm to perform a prefix search. For example, given that we have the words Google, Good, Grape in our dictionary, and a search for Goo, it should return Google and Good, but not Grape.

Follow-up 1: what happens when your prefix is an empty string?

Solved both coding with optimal approach and answered all follow-ups via code / verbally as directed by the interviewer. Interviewer seemed satisfied as I was able to complete everything before time. He asked or pointed about few special and edge case scenarios which I answered or modified in my code as per discussion.

## Interview Summary & Suggestions
During these three rounds of interviews, I demonstrated a certain level of algorithm design ability and unique problem-solving skills, but some follow-up questions were not fully addressed. I recommend that everyone prepare for interviews by ensuring coding completeness and time management, as well as focusing on resolving follow-up questions. It is also important to reinforce your algorithm fundamentals. If you encounter any difficulties or have any questions during the interview, feel free to come here to find solutions!

Google L3 SDE II Interview Experience: Rejected for the first two rounds!

OA VO Interview — Mon, 18 Aug 2025 08:43:28 +0000

Background

Two years of full-stack development experience, and a competitive programmer (Codeforces Master). Applied through Google Careers, but did not pass the referral process. Received a call from a recruiter during the first week of April, who asked about my background, experience, and salary expectations. She requested that I provide five available dates for interviews, with a maximum of two weeks between each interview to prepare. However, the actual interview dates were much later than the dates I provided.

Screen Interview

*Problem: *
I was asked a MEX kinda problem where there are sequence numbers (or frames) of type long long int and some initial sequence number x. There are two types of queries:
· Add some sequence number y
· Out of all the sequence numbers that are missing, fetch the minimum

*Solution I gave: *
Used a HashSet to store each incoming sequence number and a variable that indicates the current missing sequence number. At every insertion, the increment of the current minimum gets triggered where it gets incremented by 1 till it encounters a missing sequence number. Return this number for the query type 2. Discussed the time complexities later.

Follow up

· Why don't you trigger the increment in the get minimum call?
My answer: We can have the increment in any one of the two functions; optimal placement can be dependent on query patterns. If there are less frequent calls of query type-2, then we can place it in the get function.

· What is the real-world application of this problem? Why are we having an initial sequence number?
My answer: This is a classical video loading problem where the initial sequence number represents the starting frame of the current window and video frames < that timestamp are deleted. The missing number represents the frame that got missed and requires a retransmission.

· How do you identify the frames that are received but we are not able to process (corrupted)?
My answer: By pushing them into a HashSet whenever received and deleting from it when processed.

· How do you distinguish between the corrupted ones and the ones that are being processed?
My answer: Timestamp-based invalidation

Interview Process
Round 1：Technical Interview
Problem:
Given a garland represented by an array of size n where there are exactly d (even) diamonds and r (even) rubies, you are allowed to make at most 2 cuts to divide the array into different portions and group them into two parts such that the number of rubies and diamonds is the same in both parts.

My response:
If 1 cut: Only possible at the middle.
If 2 cuts: First and the last segment belong to the same part, so do a sliding window of fixed length n/2. O(n) solution with O(1) extra space.

Follow up:
What if there is a stone of one more type and you can make at most 3 cuts?
My response: Check for <= 2 cuts: same process as earlier.
For 3 cuts: First and third segments belong to the same part, so fix the first segment and do a similar process as earlier, yielding an O(n^2) solution. (Did not implement)

Round 2：Technical Interview
Problem:
There is an undirected graph where each node represents the home of a person. Two persons represented as nodes a and b. a and b should reach a node c while traveling independently, or both of them can club at some point and reach c. Find the minimum cost required for both of them to reach the destination (edges traversed). Note: If a and b both traverse an edge together, it is counted as cost 1.

My response:
Pre-calculate all the shortest paths from every node to every other node. Then iterate for each node and consider that a and b come to this point independently and go from here to the destination. Compare and update this distance with the answer.
Time complexity: O(n^2) (for calculating the minimum distance between each pair)

Follow up:
What if there are 3 (a, b, and d) friends that are reaching the destination c?

My response: 3 combinations: (a, b first meet, club and then meet d), (b, d first and then a), (d, a and then b). Iterate for each pair of possible joining points of the path for each combination and update the answer. (Did not implement)

Round 3：Technical Interview
Problem-1:
Given a linked list, remove a node with the given value
My response: Implemented it quickly

Problem-2:
Construct a maze of size n*m by drawing lines in canvas in such a way that there should be exactly one path possible between any two pairs of cells in the maze
My response: Initially came up with an approach where we start in the first cell (1,1), go straight if possible else turn left. This will give a spiral path in the maze. Draw lines between every two pairs of cells if there is no edge between them. Spent 10 mins explaining this idea before realizing (by self) that there is a simpler approach where we draw all the horizontal lines except for one column in each row. Explained this idea. (Did not implement)

Round 4：Technical Interview
Problem:
Given a set of lines inside an n*m rectangle, find the number of squares that can be formed.
My response: Gave solution with preprocessing and stored values in a data structure that stores the maximum length of continuous lines that are ending at the given point for each point (in both the horizontal and vertical directions). Iterate through each point and each length and check if a square can be formed using the pre-computed values. Interviewer said he was satisfied with the solution.

Interview Summary & Suggestions

Recruiters indicated that they had received negative feedback in the first two rounds. The last interviewer said he couldn't understand my solution. However, during the interview, he consistently agreed with my proposal and gave me constant affirmation. I thought I would pass the interview smoothly, but I was unexpectedly rejected. Those preparing for interviews should practice thoroughly. Don't get too excited if the interviewer gives you positive feedback, and don't doubt yourself if the interviewer is serious. Anything is possible. If you encounter any difficulties or confusion, feel free to come here to find solutions!

Amazon SDE 1 Interview Experience: I received the acceptance letter!

OA VO Interview — Fri, 15 Aug 2025 08:35:05 +0000

Timeline

January: Job application
February: Initial interview
Mid-May: Interview invitation
June: Final interview

The Interview Process

Round 1: LP+Coding
BQ 1: How do you adjust your work strategy and manage tasks when facing time pressure?

BQ 2: How do you adapt and effectively execute new tasks or goals during work transitions or changes?

2 LP questions, followed by several follow-up questions. For the second BQ, the interviewer encouraged me to choose a story that better aligns with the LP. Here, I combined my past project experience from school with the STAR method to answer. The interviewer was very satisfied with my second answer and kept nodding in agreement.

Q: Similar to designing an iterator to retrieve the next smallest number from K arrays.

Here, I used object-oriented design (OOD) and a min-heap. We discussed test cases (TC) and scenarios (SC). The initial implementation went smoothly, but I was later asked about the scalability of this solution for more arrays and how to perform arbitrary operations on K arrays. I’m not sure if my answer was correct; I suspect there may be multiple acceptable solutions. I also asked the interviewer a few questions afterward, and the conversation went smoothly.

Round 2:Coding
Q1: Merge all intervals that may overlap and return the merged result.

The key to this problem lies in sorting the preprocessing. If the intervals are sorted by their starting points, adjacent intervals can be merged in order. For example, after sorting, you only need to compare the endpoint of the current interval with the starting point of the next interval to determine whether they need to be merged. The endpoint of the merged interval is the maximum value of the two, and the starting point is the starting point of the current interval. Here, I used a greedy algorithm and solved it smoothly.

Q2: Determine whether the sum of the path from the root to the leaf of a binary tree is equal to the target value.

The DFS solution works fine. First, recursively traverse the tree, accumulate the path sum, and then determine whether it meets the target. When the current path does not meet the rules, perform backtracking.

Round 3:Coding
Q: Find the number of islands in a 2D array

The algorithm checks each position in the two-dimensional grid one by one to ensure that every land position is taken into account. By using the loops for i in range(len(grid)) and for j in range(len(grid[0])), all positions are traversed to ensure that no possible islands are missed.
When an unvisited land position is encountered, DFS is initiated to mark all adjacent land positions (adjacent in all four directions) as visited (changed to ‘0’). Once marked as visited, other land positions on the same island will not be counted again.

The DFS recursive traversal continues to expand until all adjacent land areas have been visited and marked, which exactly covers the entire range of the island. DFS ensures that each time it is initiated, it marks an entire connected land area, which meets the definition of an island in the problem statement.

Each time DFS is initiated, it means a new island has been found, so the counter is incremented by one. Through this mechanism, the final value of the counter is exactly the number of islands, meeting the problem requirements.

Follow-up: If you could turn a body of water into land, how would you operate to obtain the largest island?

This follow-up question was a bit tricky for me, but after discussing methods with the interviewer, we found the correct solution. The interviewer approved all my answers and discussed technical details and software engineering practices.

## Interview Summary & Suggestions
I received the offer letter on June 10. I recommend that everyone thoroughly research all Amazon LPs until you can recite them off the top of your head, and prepare two different STAR cases for each LP. It is best to use data in your cases to prove that your logical thinking is clear. You can also show your enthusiasm for the company and its employees. The interview process is very energy-consuming, so please be prepared physically and mentally. If you encounter any difficulties or have any questions, please feel free to come here to find solutions.

Meta New Grad Three-Round Interview Experience: Can I Get an Offer?

OA VO Interview — Thu, 14 Aug 2025 08:57:52 +0000

Timeline

September 26: Recruiter contacted me
October 4: Submitted technical + behavioral online assessment
October 7: Received final interview invitation.
November 4: Completed final interview process.

OA

For the technical, the first two felt like easies, third was an easier medium, pretty sure fourth was a medium but definitely a bit trickier. Passed all known test cases for all questions with allotted time limit. Make sure to use their 6 core values during the behavioral. I’ve heard of people getting rejected despite getting 4/4 on the technical and I feel like it’s because the behavioral is completely marginalized. Can’t imagine they’d take the time to send it if it wasn’t a part of their decision making process.

Preparation

Questions tagged with “google” on Leetcode 150 and Leetcode Premium in the past 30 days.

The Interview Process

Round 1：Coding
Q1: Given an array nums, find the length of the longest subarray with the maximum value after the bitwise AND operation.
When two numbers are subjected to the bitwise AND operation, the result is either unchanged or smaller than the original two numbers. When the two numbers are different, the result becomes smaller. Therefore, the key to solving this problem lies in utilizing this characteristic. We can conclude that the maximum value of the subarray after the bitwise AND operation equals the maximum element of the array.

Thus, this problem can be transformed into: finding the longest subsequence containing only the largest elements of the array, which is simpler. I provide a detailed explanation of the solution from start to finish, including clarification of details, test cases, and ultimately arriving at a solution optimized for both space and time complexity.

Q2: Diameter of a Binary Tree
Use DFS (Depth-First Search) to calculate the depth of all nodes in the left and right subtrees. If the node is None, it indicates that the length of this segment is 0. If the node is not None, continue searching the subtree. When reaching the bottom level, return values starting from 0 and incrementing by 1 for each level up. Update the diameter each time a value is returned.

Round 2：Behavioral
The questions I was asked:
Q1: Tell me about a past challenge or conflict you handled?
Q2: Tell me about the greatest accomplishment of your career?
Q3: Tell me about what you want to do in the future?
Q4: Walk me through your resume

I thoroughly enjoyed this interview. The interviewer left a positive impression overall, maintaining a smile throughout. He nodded in agreement with all my answers. I incorporated as many elements as possible from the six core values. My final answer was a bit shaky because I hadn’t prepared sufficiently, but I believe I had thought it through, as he didn’t provide any negative feedback. The subsequent Q&A session also went smoothly.

As I mentioned at the beginning, in recent years, the BQ interview has been the most easily overlooked yet not straightforward stage for international students applying for data roles at tech giants. Its importance is on par with coding and SD interviews. Meta’s behavioral interview questions are not standardized, and the interviewer can ask you any questions they wish.

In summary, Meta's BQ interview primarily assesses the following five areas: Resolving Conflict, Growing Continuously, Embracing Ambiguity, Driving Results, and Communicating Effectively.

Round 3：Coding
Q1: Sum of two numbers
Create a hash table Map map = new HashMap<>(), first calculate the difference, then search for the difference in the result list. If it does not exist, store it; if it exists, output it.

Q2: Longest consecutive sequence
First, create a set, then add the elements to the set and iterate through it. If the set does not contain the element preceding the current element, start counting from that element. If the element following the current element exists, move the pointer forward, increment the count, and record the maximum value in the loop.

## Interview Summary & Suggestions
I believe I have a chance of receiving an offer, but no one can say for sure about Meta. I also reached out to recruiters through campus events. However, I'm not sure if it will be useful since I've already made it to the final round. My best advice is to focus on the problems marked as “Meta” on Leetcode Premium, as this was very helpful for me—I recognized all four problem variations during the interview. Also, keep in mind Meta's six core values. If you encounter any difficulties or have any questions while preparing for the interview, feel free to come here for answers!

Amazon SDE Three-Round Interview Experience: Rejected After the Interview!

OA VO Interview — Wed, 13 Aug 2025 08:47:54 +0000

Background:
Applied for Amazon SDE New Grad (USA), completed OA in April, interviewed on June 30. Felt confident — interviewers seemed satisfied. Got a rejection email on July 8. Email had a different job ID, but recruiter confirmed it’s normal — candidates get moved to a new internal req after OA. I genuinely thought I would get it because everything went well… but here it is.

Timeline:
• April 29: Completed the OA
• May 8: Got an email asking me to verify my photo
• June 10: Followed up with the same email thread to check in — didn’t get a response
• Mid-June: Recruiter got back to me and asked for availability (I didn’t get the survey email, so I just gave dates directly)
• June 30: Final round interviews

The Interview Process:
Round 1: LP
BQ 1: Greatest challenge. Follow-up: If you could go back to that time, what could you have done better?
BQ 2: Tight deadline. Follow-up: Did you have to sacrifice other tasks?
BQ 3: Leadership. Follow-up: Asked for some details, such as how I influenced others.
The interview primarily focused on Amazon's 16 LP principles. The conversation flowed smoothly, and follow-up questions were appropriate. The interviewer seemed satisfied with my answers.

Round 2: LLD+LP
LLD：Design Bit.ly
The core requirement is that users should be able to submit a long URL and receive a shortened version, and users should be able to access the original URL using the shortened URL. This is a brief functional requirement. Non-functional requirements include ensuring the uniqueness of short codes, redirects should occur with the shortest possible delay, system availability should take precedence over consistency, and scalability to support 1 billion shortened URLs and 100 million DAUs.
The core entities in a URL shortener are the original URL, the short URL, and the user. To shorten a URL, a POST endpoint is required, which accepts the long URL along with optional custom aliases and an expiration date, and returns the shortened URL. Here, I use the POST method because it is necessary to create a new entry in the database, mapping the long URL to the newly created short URL.
To implement redirection, a GET endpoint is required, which receives the short code and redirects the user to the original long URL. GET is the correct verb here because I will read the existing long URL from the database based on the short code.
For the high-level design, the main requirement is that users should be able to submit a long URL, receive the shortened version, and access the original URL via the shortened URL. I quickly completed the design and clearly explained the approach. The interviewer seemed impressed.
LP:
Q1: Describe how you handled an unreasonable customer request.
Q2: Describe a time when you failed.
As with the previous behavioral interview, you can answer using the STAR method combined with Amazon's 16 leadership principles.

Round 3: DSA
Q1: Auto-complete: Implement insertion, search, and search by prefix.
search(word) returns true if the word has been previously inserted. startsWith(word) should return a list of inserted words that start with word.
Q2: Given a string containing digits (from 2 to 9, inclusive), return all possible letter combinations that these digits can represent.
When I see a combination problem, I immediately think of DFS/BFS. This problem is a very pure search problem with nothing special about it.

Interview Summary & Suggestions
On July 8, I received a rejection email. I truly believed I would get the job. Everything seemed to be going smoothly, and all the interviewers were satisfied with my answers. Receiving the rejection email was more disappointing than I had imagined.

Despite this, I am still grateful for this experience. It has given me a clearer vision of the future, and I now know how to improve and do better. I hope this article can help those who have gone through a similar experience.
Those of you preparing for interviews, don’t lose heart after reading my experience. I hope my experience can provide you with some insights. If you encounter any difficulties during your interview preparation, feel free to come here for solutions~

Meta Three-Round Interview Experience: Finally Landing the IC5 Position!

OA VO Interview — Tue, 12 Aug 2025 09:13:48 +0000

Background：
I have 9 years of work experience, mainly in full-stack development at some lesser-known companies. I have been working at my current position (a startup) for 2.5 years and have never interviewed at other companies during that time. I have also never participated in Leetcode-style interviews in the past. The entire process, from the initial phone call to the final hiring decision, took 8 weeks.

Preparation:
In the first two weeks, I completed all the preparatory materials on Meta's career website. I watched the corresponding videos on the HackerRank YouTube channel, which were produced by Gayle and were of high quality. Two weeks later, I took a mock interview. Finally, I spent two weeks practicing the questions most frequently asked on Meta.

The Interview Process:
Round 1:Coding
Problem:
Design a program that receives two CSV files. Requirements are as follows:

The first file contains the names of dinosaurs, their leg lengths, and their dietary habits.
The second file contains the names of dinosaurs, their stride lengths, and their postures.
Provide a formula for calculating the speed of dinosaurs.
Sort the dinosaurs according to their speed and output the sorted results for all bipedal dinosaurs. Solution: This question is more focused on data processing. My approach is to design an appropriate data structure (such as a dictionary or class) to store and process the data. Pay attention to edge cases, such as missing data or inconsistent data formats. It is advisable to prepare some common data processing questions in advance and become familiar with how to handle CSV files. If time permits, you may briefly mention how to handle edge cases.

Round 2:Behavioral
Questions:

Describe a time you faced a conflict in a project and how you resolved it.
Give an example of when you had to deliver under tight deadlines with limited resources.
Tell me about one biggest challenge. Why is it challenging and how did you overcome it?
Tell me a time when you lead a team. BQ questions are often unpredictable, and different interviewers ask questions in different styles. It is essential to prepare in advance, prepare many stories, and familiarize yourself with them. Meta behavioral interviews mainly assess five aspects: conflict resolution, continuous development, embracing ambiguity, results orientation, and effective communication.

Round 3:System Design
Problem: Design FB Post Search
The core requirement is that the system must be fast, with median queries returning in less than 500ms. It must support a large number of requests. Newly posted content must be searchable within a short timeframe (less than 1 minute). All posts must be discoverable, including past posts or less popular posts. The system must have high availability.
High-level design should include functionality for users to create and like posts. Set up an API gateway for authentication and rate limiting, along with a horizontally scalable search service to handle requests and query indexes. Enable users to search for posts using keywords.

Interview Summary & Suggestions
Ensure your code is clean, avoid unnecessary if statements and variables, and use clear function/variable names. Proper indentation enhances readability. Stick to manually running test cases. This is a great opportunity to identify and fix bugs before the interviewer intervenes. It is crucial to verbalize your thought process, as this allows the interviewer to understand your reasoning. Sometimes your mind may be focused on one thing, but you end up writing something else—at least this way, they know what you were trying to achieve. You can directly read aloud what you are typing. This is acceptable and helps convey your thought process. It also helps alleviate tension; remaining silent only makes the situation worse.

Interviews are indeed challenging, but interviewers genuinely want you to showcase your best self and have provided ample time and materials for preparation. If I can do it, so can you! Any questions or confusion can be addressed here.

Google L5 Interview Experience Sharing: Landing the Offer!

OA VO Interview — Mon, 11 Aug 2025 07:53:04 +0000

Background:
Bachelor’s from Tier 2/3 College (not sure some state govt. college). 6 years (Product based, mostly in MAANG)

Application process:
Applied through referral [However if you have strong resume for job requirement it will go through without referral as well (Applied for L4 in 2021 without referral)]

After Resume Selection:
Recruiter reachout for interviews date and explained the process. For L5, three round of DSA, one round of System design and one round of googlyness & leadership.
Recruiter told me System design and Leadership round will be conducted only if I clear DSA round ( at least 2 hire call in 3 rounds).
You will have options to have multiple round on same day or you can have it on different day as well I had all rounds on different day (DSA had ~2/3 days of gap between each round).
For System design and Leadership round I took another 3/4 weeks.
I took around 4 weeks to prepare. I would suggest, do not hurry and take your time to prepare

The Interview Process
Round 1: DSA
Problem Statement: Given a single string which has space separated sorted numbers, determine whether a specific target number is present in the string.E.g. Input: "1 23 34 123 453" Target: 123 Output: true.
Solution:I started with some straight forward brute force approach like, storing these into a list of interger and apply binary search. Apply linear search directly over the string. Final solution was applying binary search directly over the string. Constraint was that numbers would fit in numeric data type.

Round 2: DSA
Problem Statement: It was standard binary tree problem which required some calculation on it's leaf node.
Solution: I provided the DFS (inorder) solution, however interviewer asked on if BFS can be applied which was like level order traversal. Provided both the solution, fumbled a little bit in complexity analysis which I corrected when interviewer nudged me to think about different kind of trees.

Round 3: DSA
Problem Statement: Given an integer array and an integer k (1 ≤ k ≤ array length), calculate the maximum value of each contiguous subarray of length k in the array and output these maximum values.
The time complexity must be O(n), the space complexity must be O(k), and it is permissible to print the results directly without storing them.
Solution: Use a double-ended queue to maintain the candidates that may become the maximum value within the current window, ensuring that the values corresponding to the indices of the elements stored in the queue are monotonically decreasing. When a new element is encountered, first check if the head of the queue is still within the current window range; if it is outside, remove it. Compare the new element with the candidates at the tail of the queue, and remove all elements smaller than the new element to maintain the queue order. After adding the current element index to the queue, the head element becomes the maximum value of the current window.
This ensures that each element enters and exits the queue at most once. It achieves O(n) time complexity, while the queue length does not exceed k, satisfying the O(k) space requirement.

Round 4: System Design
Problem Statement: design small image/gifs/video hosting platform which does not require sign up.
Solution:
Drew high level component for the system. and explain underlying tech that can be used. e.g. storing metadata in DB (relation/non-relational) and image on file bases on storage system like S3 Had indepth discussion on relational vs non-relational. I went ahead with no-sql based db to store meta data. Provided strong points on why, I am using this Note : I did not provided loadbalancer, gateways, proxy at this point of time 4. Dig deeper into core component Discussed the bottleneck of HLD components. Then introduced, tech that can be used to solve those issues like loadbalanacer, proxies (forward, backward). Cache to store metadata. Having a background image processing system to ensure images can be stored in different format to serve all kind of user (like slow internet etc).

Interview Summary & Suggestions
Since I have already participated in several interviews, I am quite familiar with the basic concepts. While preparing for the Google interview, I tried to solve 4-5 medium/difficult level questions on Leetcode and GFG every day, and regularly participated in Leetcode competitions. I used the Needcode strategy map to ensure that I completed questions from different categories.
I learned different concepts through multiple channels on YouTube (these channels are quite popular on YouTube). After gaining a thorough understanding of the basic concepts, I began trying to solve the problems on the Needcode strategy map. This was my quick review before the interview.
There aren't many free structured resources for system design. I mainly learn through YouTube. Alex Xu's book, System Design Interview: An Insider's Guide, is very helpful for improving skills and preparing for interviews.
For senior positions, it is generally expected that the interviewee will lead the entire system design interview. The interviewer only needs to present the scenario, and the interviewee will explain how it is currently handled or how it will be handled in the future. During the interview, the interviewee should continuously share their thought process while maintaining an open attitude to accept feedback and adjust in that direction.
If you encounter any confusion while preparing for an interview, you can visit ProgramHelp to find solutions. It will assist you in overcoming technical challenges, and enhance your problem-solving skills.

Five-round interview process of Google: Finally landed the offer!

OA VO Interview — Fri, 08 Aug 2025 08:53:30 +0000

Company Introduction

Google’s process is one of the most transparent among major tech companies. It’s lengthy and can be stressful, but you rarely get ghosted or rejected for unclear reasons.

Application & Recruiter Outreach

Early February

I submitted three applications for Software Engineer, Early Career, via the Google Careers portal.
Initial Outcome

All three were rejected after about a week. I’d previously applied via referral for other roles and was similarly rejected before any interviews.
Surprise Outreach

Three days after those rejections, an external recruiter contacted me to discuss my background and aspirations. After a five-minute conversation, she felt I was a strong fit and scheduled my phone screen once I confirmed my preferred language and availability.

Interview Process

Round 1: Phone Screen

Preparation

I asked for three weeks to prepare; Google scheduled the screen in two. I re-reviewed the Neetcode 250 list and did mock interviews with two friends (one Google engineer, one Amazon engineer).
Questions
1. Introductions and background questions
2. One “easy–medium” algorithmic problem (string manipulation plus basic data structures)
  - Approach: Use two pointers, moving from the beginning and end toward the middle. If the characters at both ends are not equal, try deleting one character on the left or right, then check if the remaining part is a palindrome. If either method can make it a palindrome, return True.
3. One “medium” follow-up adding an extra data-structure requirement

Round 2: Technical 1

Question

A 2D dynamic-programming problem on a matrix with constraints. I recognized the DP pattern and used tabulation.
Approach

Compress the two-dimensional state array into a stack and use data structures (such as balanced trees and monotonic queues) to accelerate state transitions. Also use recursion and caching to avoid redundant calculations.

Round 3: Technical 2

Question

An unbounded-knapsack-style DP hidden behind a creative problem statement.
Approach

Consider the array being used, which reduces the space complexity, requiring only two rows. The optimized method is similar to the original DP approach, except that dp is changed to one row, and each time a current array curRow is initialized. After updating the current array, dp is overwritten, and the next row is updated.
Follow-up

Design questions about operational optimization

Round 4: Googliness (Behavioral)

Questions
1. Tell me about a time you had to handle a project that was late
2. Tell me about how you work with difficult people/stakeholders
Approach

I did not prepare any case studies in advance. I used the STAR method on the spot to share real stories about my past experiences and the lessons I learned.

Round 5: Technical 3

Question

A variation on KMP
Approach

Find the common prefix and suffix of the matching strings, and the position pointed to by j is after the common prefix and suffix found.
Follow-up

Asked to optimize. I discussed the double pointer method, but there was a problem with the code. I immediately discovered the edge case, but by then I had already been asked to stop coding.

Later Situation & Suggestions

The recruitment consultant reported that the feedback from the fifth round was mixed, and there was a risk of rejection by HC. HC then added another round of technical interviews, and I requested an extra week to review data structures and algorithms.

Key Advice:

It is important to have a solid foundation of basic knowledge.
Core data structures and algorithms (DSA) and system design skills are sufficient to handle the interview process.
Use high-quality resources, such as Neetcode 250, for preparation.

Whether you are a beginner or an experienced developer, finding the right learning resources is crucial. Let ProgramHelp help you achieve a better professional future.