Adobe Interview Experience | MTS-1

Status and Background

I was working as an SDE-1 at Samsung Research Institute Delhi and graduated in 2018 with a B. Tech. in Computer Science from NIT Kurukshetra, India. My interview for the MTS-1 position at Adobe Systems in Noida, India took place on May 1, 2019.

1. Online Assessment Test (HackerRank)

The first stage was an online assessment on HackerRank. It comprised:

• 15 aptitude questions (15 mins)
• 5 input-output programs (15 mins)
• 2 programming questions (45 mins)

2. On-site Round 1 - Technical Round (1 Hour)

This round began with a discussion on my projects, including their architecture diagrams. Following that, I was asked several programming and theoretical questions:

• How to sort an array containing 0s and 1s in a single pass with O(n) time and O(1) space complexity.
• A problem to add 1 to a number represented as a singly linked list. Each node represented a digit, with the head pointing to the most significant digit. The challenge was to do this in a single traversal.
• I had to determine the number of different ways to form an N-bit binary number such that no two consecutive 1s occur. For N=3, examples like 101, 010, 000, 001, 100 are valid (output: 5), while 110, 111, 011 are invalid. I wrote a program, but the interviewer mentioned there's also a mathematical formula for it.
• I was asked about the Producer-Consumer problem, including writing pseudo-code. We also discussed semaphores, mutexes, critical sections, and potential deadlock scenarios involving wait() and signal() operations.

3. On-site Round 2 - Technical Round (1 Hour)

This round involved a deep dive into one of my projects. The interviewer skillfully transformed the project discussion into a problem and posed many follow-up questions. The core problem was:

How would you represent an image in memory, for example, as a matrix where each cell is a pixel? Considering a monochrome image represented by such a matrix, how would you programmatically draw a line segment on it? This meant filling the cells that the line segment would pass through. I had to account for both axis-aligned and non-aligned line segments and write a program for it. I initially assumed integer endpoints for the line segment and coded accordingly. The interviewer then challenged me on whether the code would work for float/double endpoints and we discussed generalizing the solution. We also covered boundary cases: what if the line segment's endpoints are outside the matrix, or if the segment is only partially inside? For a line segment not aligned to any axis and not bounded by the matrix, I was asked how to find the point where it first enters or exits the matrix.

4. On-site Round 3 - Technical Round (1 Hour)

This round covered a mix of C/C++ fundamentals, data structures, and algorithms:

• Questions on pointers, such as the validity of pointer differences and pass-by-reference in functions.
• What happens when an object of a class is declared and memory is allocated to it?
• Questions on object-oriented programming concepts like inheritance, polymorphism, and virtual functions.
• I was asked to implement a Hash Table with the following APIs: void insert(int key, int value), void delete(int key), int search(int key), and int getRecentElement(). The getRecentElement() API should return the key of the element most recently touched by either insert() or search(). All APIs were expected to operate in O(1) time, assuming no duplicate keys.
• A problem to search for an element in an array where each consecutive pair of elements differs by exactly 1 (i.e., |A[i] - A[i+1]| = 1 and |A[i-1] - A[i]| = 1).
• Given N threads and single instances of N different types of resources, how would I allocate resources to threads to avoid deadlock and minimize waiting time? This assumed threads could arrive at any time and request any number of resources, without knowing their arrival schedule.

5. On-site Round 4 - Director Round (1 Hour)

This was a broader discussion round:

• We discussed my projects.
• I was asked how to identify whether software I'm about to install on my PC is malware, providing methods for both pre-installation and post-installation.
• Following up on that, I was asked how to identify if the software had deleted or added files to my file system. I suggested comparing the file system's tree structure before and after installation.
• Building on the previous question, I was given two files containing lists of file names (representing states before and after installation) and asked to write pseudocode for a fileDifference(File A, File B) function to find the differences.
• A combinatorics problem: Given an N x N matrix, how many ways are there to reach the top-right corner from the bottom-left, moving only Up, Right, and Up-Right diagonally? I used a dynamic programming approach, but the interviewer prompted me to derive a mathematical formula. (I later learned this relates to Delannoy Numbers).

6. On-site Round 5 - Manager Round (1 Hour)

The final round was with a manager, focusing on problem-solving and logic:

• I had to write a program to convert a number into English word format, specifically using the Indian Currency system (e.g., 1,23,500 to “One Lakh Twenty Three Thousand Five Hundred”, 100 to “One Hundred”).
• Another task was to write a program to check if two given binary trees are mirror images of each other.