Intro

I got placed in Arista Networks a a while back through their on campus hiring. Little bit of background about me:

• B.Tech Final Year Student
• Tier 1 college
• Over 650 questions on LC, and many more on other platforms.
• 1360+ CF Rated

Rounds

They (Arista) came on campus for hiring and the process was as follows

1. Online Assessment on HackerRank (heavily proctored, good thing!)
2. 2 Technical interview rounds
   a. Resume, Operating Systems, Leetcode
   b. Leetcode and little system design
3. HR Round

Compensation

• 16L Base
• 5L retention and joining bonus
• 12000$ (10L) stocks, vested over a period of 2 Years.

Questions

Online Assessment:

There were 2 sections

• MCQs
• Coding Questions

MCQs :
The MCQs were a mix of CS fundamentals, DSA, linux, operating systems, C/C++ programming, etc.
For instance take this question:

int x = printf("hello");
switch (x) {
	case 1:
		printf("1");
		break;
	case 2:
		printf("2");
		break;
	... // extra conditions
}

This is not the exact question, but similar to this. Some questions were based on linux as well, like how will you kill a process with a particular id, kill -9 <pid>, but not only this there were some other syntaxes given as well.

Coding questions :
There were 3 coding questions in total. They were of medium-medium to medium-hard category, but they were different for everyone.
One catch the available languages were only C/C++ and JAVA.
They were as follows for me I do not recall exact questions, but all of them were leetcode style, I am adding topic for reference, that I remember correctly.:

1. This question went like this, there were given N chocolates, each had some parameter, say weight. Now on each day I can eat only one chocolate and it's weight will be halved, 2->1, 1->0. I need to minimize the number of days. [PRIORITY QUEUE]

Example TC:
C1: 12
C2: 4
C3: 6
Answer:
C1,C1,C3,C2,C1,C3,C2

2. This questions was similar to this, there was a word, I need to make it lexicographically the maximum, but the condition was to make sure there are no more than K consecutive occurrences of the same letter. [PRIORITY QUEUE]

3. This question goes like, there are some intervals, I needed to merge them based on some condition making sure some other metric. This was the hardest among these, but was also based on priority queue. [PRIORITY QUEUE]

Status: 2/3 Solved (1,3) and in the interview I solved the 2nd one too.

Verdict: Selected, only 10% were shortlisted, (10 people if I remember correctly).

The test completed around 10:00 PM, and the results were declared at 12:30 AM and the interviews began at 08:30 AM.

Interview

There were 2 technical interview rounds and they were as follows:

1. This round was oriented on OS concepts and DSA. The round started and the interviewer was very friendly despite his experience. He was looking at my resume as asked some questions based on my internships and projects, as all of my internships were in startups he confirmed wether they still existed or not (they did😂😂). Then he started with questions:

• He first gave me a C++ code and asked me to identify error in it. ✅
• He then gave me another C++ code with passing pointer in a function and asked to fix error in it. ✅
• Then he moved on to the OS part, he asked me about various states of a process. ✅
• Difference between orphan and zombie process. Orphan ✅ Zombie: I was not able to provide an example as i never experimented to make any zombie process. He then grilled deep onto zombie process. All the time he gave me a lot of hints but I was not able to tell the answer perfectly.
• QUESTION: suppose there is a timeline say 100 seconds long. main starts at 0s, forks a child at 5s then goes to sleep till 100s. The child completes it's task in 25s. Tell the states for main and child process.
• Then he told me the answer and we moved away from this questions.
• He then gave me yet another code, this time a bigger one and asked to me find eros in this and cases where it won't work. This was based on exec and what happens when and exec fails. ✅
• He then said coding sahi hai pr os thoda idhar-udhar hai😅(translation: Coding is good but OS is little weak) .
• He then gave me DSA questions 2:
  • In a BST find whether sum of any path till leaf is X. Since I had already received a complement for my coding I did not care and directly gave the optimal answer.
  • Articulation point: For this he asked me wether I knew what it is, i told him the definition and told the answer on one example. The again wrote the optimal code directly.
  • He was happy on seeing the solution. I asked for feedback, he didn't give me. I also asked som questions about types of team in arista and some questions based on why Python was not allowed as a language in OA. Then we left.

Soon after this first round my second round began

2. I went in the room with my laptop, greeted the interviewer. He asked me will I use my notebook or laptop, I said laptop but it was discharged. I then apologized, rushed to get the charger, cam back, I had to ask the interviewer to unplug their laptop's charger so that I can plug mine🤦🏻 . He was very calm and understanding and understood my situation and said it's completely fine. So this round began:

• He gave me n integers, they were unsorted and n-1 of them were consecutive. I needed to find which number was missing. (I don't know but the seniority of the interviewer intimidated me.) I first gave a mathematical solution. He said it was okay, then asked me to provide a DSA solution. i did it with hash map.
• We discussed on the bounds of the problem for some time, I dry ran it in-front of him and he was happy with the solution.
• We then moved to the design question, it went like this

You are given a router, it needs to assign IDs to anyone who connects to it. The ID will be always >= 0. 
One can disconnect to the router and free the ID assigned to it.
I needed to design a library, and one of it's function was to assign and free the ID in the router. 
I needed to do this in the least amount of time and space.

• I started by asking how the router will be used, the amount of devices it will serve. Space restrictions, propagation delay (in case of a nested structure), etc. Once the requirements were clear, I just needed to show the structure of the class. I used a linked list whose head (if not null) will be assigned to any newly connected device and if null then use an integer counter to give the ID. Once the integer counter is full and head is null, that means the router has reached its service capacity.
• He was happy with the solution. This interview round lasted 20-25 mins, I knew smaller rounds means less interest so I made sure I ask ample questions to make sure that they know I am interested in the company. I asked few questions which the interview explained deeply. This made sure the interview was 40-50 mins long.

Verdict : Passed the technical round

HR Round:

I was most anxious about this round because I was rejected in this once. This round went as follows:

• How were your interviews?
  • Me: Good! (like seriously!!!!)
• The HR (waiting for me to speak more) : and!
  • Me: The interviews were good and humble and helped me whenever i got stuck. (again seriously!!!!!)

She understood😅😅 i don't know what but she did and did not dig deeper.

• Where do you see yourself in 5 years.
• Any plans for higher studies.
• Told about compensation.
• She asked me if I had some questions. I asked some.

Verdict : Accepted offer, I had no competing offer or internship.

Extra questions:

These were asked to my batchmates.

• Design MMU
• How does garbage collector work in Java
• Other DSA questions (leetcode style mostly)

Tips

• Focus on OS
• Do LC, you never know where will you see the problem.
• Don't lose hope. I was not placed on campus for any internship, and a company who came before arista I did not even cleared the OA.
• KEEP GRINDING!!!!

You can comment any other questions that you have I will be happy to answer them.