Lifesight Software Developer Interview Questions and Answers

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. 
Validate if a given binary tree is a Binary Search Tree (BST) or not.
• Check if the left subtree of a node contains only nodes with data less than the node's data.

• Check if the right subtree of a node contains only nodes with data greater than the node's data.

• Recursively check if both the left and right subtrees are also binary search trees.

• Example: For each node, validate if its left child is less than the node and right...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. 
Find the longest substring with at most K distinct characters in a given string.
• Use a sliding window approach to keep track of the characters and their counts in the substring.

• Maintain a hashmap to store the characters and their frequencies.

• Update the window size and characters count as you iterate through the string.

• Return the maximum length of the substring with at most K distinct characters.
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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. 
Detect if an undirected graph contains a cycle.
• Use depth-first search (DFS) to detect cycles in the graph.

• Maintain a visited array to keep track of visited vertices.

• If a visited vertex is encountered again during DFS, a cycle exists.

• Consider disconnected graphs as well.

• Example: For input N=3, Edges=[[1, 2], [2, 3], [1, 3]], output is Yes.
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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. 
Given constraints and rules, find maximum vaccines administered on a specific day during a vaccination drive.
• Iterate through each test case and calculate the maximum number of vaccines distributed on the specified day.

• Distribute vaccines evenly across days while maximizing the number on the specified day.

• Ensure that the sum of vaccines administered does not exceed the maximum allowed.

• Consider edge cases like when the n...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. 
Find all unique combinations in an array where the sum is equal to a given target sum, with elements in non-decreasing order.
• Use backtracking to generate all possible combinations of elements in the array that sum up to the target sum.

• Sort the array to ensure elements in each combination are in non-decreasing order.

• Handle duplicate elements in the array to avoid duplicate combinations.

• Consider edge cases like empty arr...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. 
Sliding window maximum problem where we find maximum element in each window of size K.
• Use a deque to store indices of elements in decreasing order within the window.

• Pop elements from the deque that are out of the current window.

• Append the maximum element from the front of the deque to the result for each window.
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