Lifesight Interview Questions, Process, and Tips

Q1. Write an SQL query to join tables
Ans. 
SQL query to join tables
• Use the JOIN keyword to combine rows from two or more tables based on a related column between them

• Specify the columns to be selected from each table

• Use ON clause to specify the join condition
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Q2. How would you expand your product to a new market
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Q3. Questions about their product
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Q4. Questions about past experience
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Q1. Behaviour based product questions
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Round duration - 75 Minutes
Round difficulty - Medium

This round was with SDE-1 
After my introduction , he asked me 3 Questions
 

Q1. 
Validate Binary Search Tree (BST)
You are given a binary tree with 'N' integer nodes. Your task is to determine whether this binary tree is a Binary Search Tree (BST).
BST Definition:
A Binary Search Tr...read more
Ans. BST property
The approach is based on the fact that the value of each node in a BST is greater than the value of all the nodes in the left subtree and smaller than the value of all the nodes in the right subtree.
 
Here is the complete algorithm-
• For each node, we store the minimum and maximum value allowed for that node. Initially, for the root node, the minimum value would be -10^9 and the maximum value should be 10...read more
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Q2. 
Longest Substring with K Distinct Characters
You are provided with a string S of length N, consisting of lowercase English alphabet letters, and a positive integer K.
Your task is to determine the maximu...read more
Ans. Brute Force
• We will generate all the substrings using two nested loops and have a ‘check’ function which returns ‘true’ if the number of distinct characters in the substring is less than equal to K, otherwise ‘false’.
• We will have a ‘longestLength’ variable initialized to 0. We will call the ‘check’ function with every substring, and if it returns true, then:
  • ‘longestLength = max(longestLength, currentSubstring.size())’
• To...read more
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Q3. 
Cycle Detection in Undirected Graph Problem Statement
You are provided with an undirected graph containing 'N' vertices and 'M' edges. The vertices are numbered from 1 to 'N'. Your objective is to determi...read more
Ans. DFS Approach (Slow)
There is a cycle in the graph only if there is a back edge (back edge is an edge that connects a vertex to another vertex that is discovered before it's parent) present in the graph. To detect a back edge, we will keep track of vertices that have been already visited. If we reach a vertex that is already visited and is not the parent vertex of the current vertex, then there is a cycle in the graph.&n...read more
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Round duration - 90 Miinutes
Round difficulty - Medium

This round was with a Senior Data Engineer as this position was a mix of Backend and Big Data.

 

Q1. 
Covid Vaccination Distribution Problem
As the Government ramps up vaccination drives to combat the second wave of Covid-19, you are tasked with helping plan an effective vaccination schedule. Your goal is...read more
Ans. Brute force
The idea is to choose a peak value at the ‘dayNumber’ th index. Then we can create the array like a mountain with the peak of the mountain being at the  ‘dayNumber’ th index. The sum of the elements of this array must be less than or equal to maxVaccines.If we find that the sum is greater, then we have chosen a high peak value, and if it is less, then it means we have chosen a smaller peak value. So we ...read more
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Q2. 
Combination Sum Problem Statement
Given an array of distinct positive integers ARR and a non-negative integer 'B', find all unique combinations in the array where the sum is equal to 'B'. Numbers can be c...read more
Ans. Recursive Approach
We can use a backtracking approach to generate all the valid combinations.
 
The approach will be:
• We will sort the array/list ‘ARR’ in ascending order.
• Let the current sum of the combination on which we are recursing over be ‘currSum’ and the index which we are on in the array/list  ‘ARR’ be ‘currIndex’.
• In each recursive call, we will:
  • While currSum <= B:
    • Increase ‘currSum’ by ARR[currIndex].
    • ...read more
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Round duration - 75 Minutes
Round difficulty - Easy

This round was taken by Engineering Manager
There were 2 sections to this round
Technical and Non Techincal
 

Q1. 
Sliding Window Maximum Problem Statement
You are given an array/list of integers with length 'N'. A sliding window of size 'K' moves from the start to the end of the array. For each of the 'N'-'K'+1 possi...read more
Ans. Brute Force
Our intuition here is to go through each sliding window and keep track of the maximum element in each sliding window. To implement the same we run two nested loops, where the outer loop which will mark the starting point of the subarray of length k, the inner loop will run from the starting INDEX to INDEX + K, K elements from starting index and store the maximum element among these K elements into the answer...read more
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