Zscaler Interview Experience | On-Campus 2021

Hi all, Zscaler came for On-Campus Hiring in our College with two roles: DEV and DEVTEST. I was given the role of DEV JAVA API.

Round 1: Coding Round (JAVA DEV): 2 hrs

• Study the pattern of the recruitment process before sitting in any company. See what type of questions they ask. You can only do this when you know what the company is because the question type also depends on the company type. Type implies whether it is networking-based, security-based, application-based, real estate-based, banking-based, etc.
• Avoid malpractice in the MCQ or Coding Round. If you are selected by chance for the interview then they can find that you have copied from somewhere else. If you are not able to think of some algorithm techniques then always try brute force approach (a straightforward). You will be asked in the interview to optimize your code.

Tips to clear the coding round:

1. Plan a coding test for yourself either in Leetcode or HackerRank.
2. Set a timer of 1.30 hrs-  2hrs for 4 questions and try to complete it.
3. If you are not able to complete within the timer set by you, then stop the timer, evaluate the code by yourself.
4. Give another 1 hour to solve the undone problems.
5. Still you are not able to solve that, then search on the internet and trace the algorithm.

Questions in ZSCALER Coding Round for Java Dev

I solved 3 out 4 with 100% output.

1. Ancestral Sorting

   Given list of strings s[] = {“John VII”, David V, John V, Henry VI, Henry IV};

   Output: {David V, Henry IV, Henry VI, John V, John VII}

   Technique to solve it:

   Convert the single value list to paired value lists. Use any sorting algorithms, preferably quick sort to pass all the test cases and design a comparator function to embed it in the sorting function.

   In C use:  https://www.geeksforgeeks.org/comparator-function-of-qsort-in-c/

   In C++ use: https://www.geeksforgeeks.org/sort-c-stl/

   In Java use: https://www.geeksforgeeks.org/comparator-interface-java/

2. Spin Wheel Question

   It was based on elimination of round wise maximum elements from a 2D matrix.

   7 1 2          1 2              1

   2 4 6   ->    2 4     ->     2      ->      [ 7 + 4 + 2] = 13

   3 1 2          1 2              1

   Hint: Stack for storing the maximum element in one round. [7, 1, 2]

3. Problem on Merge sort (Inverse Swap count):

   The problem was a little tricky. Solving merge sort problems for competitive programming study divide and conquer and how to link a problem with divide and conquer.

   Refer: http://www.dhimangaurav.com/docs/data.pdf

4. String problem

   Given a string containing values from 0 to 9. The problem was to find the number of substrings in which all the different characters occur exactly k times.

   Refer: https://www.geeksforgeeks.org/number-substrings-count-character-k/

   Hint: Use hashing concept. It will definitely solve all the test cases also for large values.

Tips to clear Interview Rounds:

1. Be 1000000…….n% before sitting in the interview. Remove all kinds of weird thoughts and only focus on the interview.
2. During the interview if you feel nervous, don’t let the interviewer feel it.
3. Be honest, I mean be truthful. If you have the answer to the particular question then answer with full confidence.
4. If you don’t know the answer to a particular question then say politely: “Sir I don’t know the answer to this question.”. You will get honesty points in this.
5. If you are confused in throwing any answer to a particular question then, tell the interviewer that “I attempt it and I will try”. While trying, ask the interviewer about what difficulty you are facing. This will lead the interviewer to think that the candidate is trying to learn. This adds to honesty rewards

Technical Interview 1(Programming Fundamentals): 45 mins

• Tell me about yourself
• I am XYZ from abc college currently pursuing 3rd year, Btech, Computer Science and Engineering (Not CSE, respect the department while saying it).
• My hobbies are these
• My strength is this (make sure that your strength should benefit the company)
• My Weakness is this (opposite)
• Theme: OOPS, SQL, Programming fundamentals, Coding round questions explanation.

Technical Interview 2(Data Structures and Algorithms Skills and Database Fundamentals): 45 mins

• Questions were from Comparator Sort, Deep Algorithms (All basics)
• I was asked to explain my project in which I have used my skills. Make sure that you are 100000……n% confident while explaining. Your next round selection depends on it.

Technical Interview 3(Mixed Variations: Networking, Security, Testing, Deployment, Git, Algorithms): 45 mins

• Awareness Questions were asked:
• Are you aware of using lambda expressions are implemented in Java.
• Answer: No sir, I am not aware of it . I can only say what exactly this is. The interviewer will then give you the chance to explain then, he will help you to understand what the concept is and how to implement.
• Questions were from Computer Networks, Java fundamentals (ex: OOPS, Static and final variables, Memory layout of JAVA, Collections)
• Example: When will you use ArrayList and LinkedLiist in JAVA.

Result: I got selected for the role of  Dev in JAVA API