Signify Innovation Labs interview experience Real time questions & tips from candidates to crack your interview

SDE - 1

Signify Innovation Labs
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4 rounds | 8 Coding problems

Interview preparation journey

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Journey
I was in the second semester of my first year of M.Tech when I learned that Signify was hiring for an SDE Intern + PPO role. Since I was part of the TPO team, I requested that the company be invited to our campus. I had already been practicing competitive programming and DSA, so I was well prepared. After the company visited the campus, I appeared for the online assessment and cleared it, followed by the interview.
Application story
Since Signify visited our campus, I applied directly through the portal. It took around 2–3 days for the resume to be shortlisted and for the test link to be shared. After three days, we received the online assessment link. Upon clearing it, we received the interview slot details the next day. On the following day, I attended all three interview rounds and received the results on the same day.
Why selected/rejected for the role?
I was selected for the role. All my interview rounds went very well. I was able to answer all the questions, as the DSA and computer science questions were generally of medium difficulty.
Preparation
Duration: 3 months
Topics: Data Structures, Greedy Algorithms, Dynamic Programming, Linked Lists, Trees, Graphs, Semaphores, ACID Properties, Functional Dependencies, TCP/IP Protocol, WebSockets, etc.
Tip
Tip

Tip 1: Focus on solving problems (not limited to DSA; aim for an all-round approach).

Tip 2: Develop a strong grip on computer science fundamentals.

Application process
Where: Campus
Eligibility: 7.5 CGPA, (Salary Package: 14 LPA)
Resume Tip
Resume tip

Tip 1: Prepare your resume according to the job description.

Tip 2: For on-campus opportunities, the ATS score doesn’t matter much. However, for off-campus applications, aim for an ATS score above 80 for easier shortlisting.

Interview rounds

01
Round
Medium
Online Coding Interview
Duration90 minutes
Interview date9 Feb 2025
Coding problem2

It was the first round, which consisted of MCQs and coding questions conducted on a coding platform. We had to take the test in the campus computer lab under AI proctoring, with invigilators also present. The round included 40 questions based on basic aptitude, reasoning, OOPs, and computer science fundamentals, followed by two coding questions. One coding question was of medium difficulty and based on graph data structures, slightly above the typical medium level. The other was an easier question on custom object sorting, which could be attempted only in the C language (only the second question was restricted to C).

1. Reverse Edges

Moderate
20m average time
80% success
0/80
Asked in companies
SamsungBNY MellonNutanix

You are given a directed graph of ‘N’ nodes and ‘M’ edges. Also, you have two nodes ‘A’ and ‘B’. Your task is to make at least one valid path from ‘A’ to ‘B’ by doing the below operations a minimum number of times.

Choose two nodes ‘X’ and ‘Y’, such that there exists an edge from ‘X’ to ‘Y’.

Delete edge ‘X’ to ‘Y’.

Add edge ‘Y’ to ‘X’.

You need to print the minimum operations that you have done.

Problem approach

I created an adjacency list where:

u → v has a weight of 0, and v → u has a weight of 1.

I used a deque instead of a queue:

  • If the edge cost is 0, I push the node to the front.
  • If the edge cost is 1, I push the node to the back.

I maintained a distance array initialized to infinity.
Starting from the source node S, I kept relaxing edges similar to Dijkstra’s algorithm, but using the deque-based approach.
Once the destination node D was reached, the stored distance represented the minimum number of edge reversals required.

Try solving now

2. Player Leaderboard Sorting

Easy
0/40
Asked in company
Signify Innovation Labs

You are developing a leaderboard system for a game. You are given a list of N players, where each player is represented by their name and their score.


Your task is to sort this list of players and print the resulting leaderboard according to two rules:

- Players should be sorted in descending order of their scores (highest score first).

- If two or more players have the same score, they should be sorted by their names in ascending lexicographical (alphabetical) order.


Problem approach

Use Merge Sort to solve this problem because:

  • It is stable, which is important when applying multiple sorting rules.
  • It guarantees an O(N log N) time complexity.
  • It works well with arrays and structures and fits within the given constraints.
  • It is explicitly mentioned that library sorting functions like qsort should not be used.
Try solving now
02
Round
Medium
Video Call
Duration45 minutes
Interview date14 Feb 2025
Coding problem2

It was based on two DSA questions, both of which were of medium difficulty. The interviewer was friendly and guided me properly in areas where I was going wrong. Overall, it was a very good interview.

1. Online Stock Span

Moderate
30m average time
70% success
0/80
Asked in companies
AmazonGoldman SachsWalmart

Ninja Coin is a famous crypto-currency in Ninja Land. Ninja has an array/list ‘PRICE’ of size ’N’ where ‘PRICE[i]’ is the price of a Ninja Coin on an ith day in INR, where 0 <= 'i' <= N-1.

The span of the Ninja Coin price on an ith day is defined as the maximum number of consecutive days (starting from the ith day and going backward) for which the price of a Ninja Coin was less than or equal to its price at ith day.

Your task is to return an array/list of size ‘N’ where the ith integer is the span of Ninja Coin price on an ith day. Go through the example for more clarity.

For Example :
Let the price of Ninja Coin for 5 consecutive days is [4, 2, 3, 3, 7].

Then the span of Ninja Coin on the 0th day is 1 because we cannot move backward from day 0.

The span of Ninja Coin on the 1st day is 1 because the price on day 0 is 4 which is greater than 2, so the only day 1 is counted.

The span of Ninja Coin on the 2nd day is 2 because the price on day 2 and day 1 is less than or equal to 3 and then on day 0 price is 4 which is greater than 3, so we count day 2 and day 1.

The span of Ninja Coin on the 3rd day is 3 because the price on day 3, day 2, and day 1 is less than or equal to 3, and on day 0 price is 4 which is greater than 3, so we count day 3, day 2, and day 1.

The span of Ninja Coin on the 4th day is 5 because its value is higher than all previous days values.    

Thus you should return an array/list [1, 1, 2, 3, 5].
Problem approach

The idea is to use a stack to directly find the first previous greater element for each day, instead of checking all consecutive smaller elements. Once we know that index, we can compute the span as:

Span[i] = currentIndex − indexOfPreviousGreaterElement

Try solving now

2. Swap Nodes in Pairs

Moderate
40m average time
60% success
0/80
Asked in companies
WalmartOLX GroupAmazon

You are given a singly linked list of integers.

Your task is to swap every two adjacent nodes, and return the head of the modified, linked list.

For Example:

We have a linked list 1->2->3->4->5->6->7 and so on. You are supposed to swap pairs of a linked list like swap (1,2), (3,4), (5,6), and so on.
Note:
1. You may not modify the data in the list’s nodes; only nodes themselves may be changed. Because imagine a case where a node contains many fields, so there will be too much unnecessary swap.

2. If a pair of a node does not exist, then leave the node as it is.
Problem approach

The idea is to swap the data of the first two adjacent nodes and then recursively move to the next pair of nodes. In each recursive call, the data of the current node is swapped with that of its next node, and the function continues until there are fewer than two nodes left in the list.

Try solving now
03
Round
Medium
Video Call
Duration45 minutes
Interview date14 Feb 2025
Coding problem3

This round was primarily focused on basic HLD questions, such as how to scale a system, the factors involved, where to use caching, and how to improve system performance. It was followed by an LLD discussion, where I was asked a complete design question along with more detailed OOP-related queries. I was also asked to design a simple class diagram for a parking system and then implement it.

The interviewer was very nice. I got stuck at a few points, but they helped me work through them and made the interview interactive. Overall, it went really well.

This was a Technical + Managerial round based on the skill set mentioned in my resume. The round may differ for others depending on their resumes. Since the interviewer was from the team I would be working with after selection, the main focus was to assess my knowledge in relevant areas. This can vary for other candidates.

1. System Design

Design a simple class diagram for a parking system and then implement it.

2. System Design

Explain how to scale an HLD system and the factors involved.

3. System Design

Explain the use of caching and how to make the system faster.

04
Round
Medium
HR Round
Duration30 minutes
Interview date14 Feb 2025
Coding problem1

It was a general HR round, mainly focused on getting to know me better as a person. The HR asked questions about my background, current location, family, and my interest in and willingness to relocate to Bangalore for the role. They also discussed my past work experience, the types of projects I have worked on, and my overall career journey so far.

The conversation was quite friendly and relaxed. The HR aimed to understand my motivation for joining the organization, how I align with the company’s values, and my expectations regarding the role and work environment. Overall, it was a smooth and positive discussion focused on assessing both my professional and personal fit for the position.

1. HR Questions

  • They asked me about my background, current location, and family, and also inquired about my interest in and willingness to relocate to Bangalore for the role.
  • They also asked me to talk about my past work experience.

Here's your problem of the day

Solving this problem will increase your chance to get selected in this company

Skill covered: Programming

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