Rocketlane Software Developer Interview Questions and Answers

Round duration - 60 Minutes
Round difficulty - Easy

Q1. 
Level Order Traversal Problem Statement
Given a binary tree of integers, return the level order traversal of the binary tree.
Input:
The first line contains an integer 'T', representing the number of te...read more
Ans. 
Return the level order traversal of a binary tree given in level order with null nodes represented by -1.
• Create a queue to store nodes for level order traversal

• Start with the root node and add it to the queue

• While the queue is not empty, dequeue a node, print its value, and enqueue its children

• Repeat until all nodes are traversed in level order
Answered by AI
Add your answer

Round duration - 45 minutes
Round difficulty - Easy

Q1. What is a deadlock in DBMS, and can you explain the concepts of join and query?
Ans. 
A deadlock in DBMS occurs when two or more transactions are waiting for each other to release locks, causing them to be stuck indefinitely.
• Deadlock is a situation where two or more transactions are unable to proceed because each is waiting for the other to release locks.

• To prevent deadlocks, DBMS uses techniques like deadlock detection and prevention algorithms.

• Joins in DBMS are used to combine rows from two or more ta...read more
Answered by AI
Add your answer

Round duration - 60 Minutes
Round difficulty - Medium

Q1. Design a system for Twitter, outlining the key components and architecture involved.
Ans. 
Design a system for Twitter
• Key components: user profiles, tweets, hashtags, timelines

• Architecture: microservices, load balancers, databases, caching

• Scalability: sharding, replication, CDN

• Real-time processing: streaming APIs, push notifications
Answered by AI
Add your answer

Round duration - 60 Minutes
Round difficulty - Medium

Q1. 
Maximum Subarray Sum Queries
You are provided with an array of ‘N’ integers and ‘Q’ queries. Each query requires calculating the maximum subarray sum in a specified range of the array.
Input:
The first ...read more
Ans. 
Implement a function to calculate maximum subarray sum queries in a given range of an array.
• Iterate through each query and calculate the maximum subarray sum within the specified range using Kadane's algorithm.

• Keep track of the maximum sum found so far and update it as needed.

• Return the maximum subarray sum for each query in the test case.
Answered by AI
Add your answer
Q2. 
Sort 0 1 2 Problem Statement
Given an integer array arr of size 'N' containing only 0s, 1s, and 2s, write an algorithm to sort the array.
Input:
The first line contains an integer 'T' representing the n...read more
Ans. 
Sort an integer array containing only 0s, 1s, and 2s in linear time complexity.
• Use a single scan over the array to sort it in-place.

• Maintain three pointers for 0s, 1s, and 2s and swap elements accordingly.

• Example: Input: [0, 2, 1, 2, 0], Output: [0, 0, 1, 2, 2]
Answered by AI
Add your answer

Round duration - 20 Minutes
Round difficulty - Medium

1st round is coding assessment round based on graph and hashmaps

Q1. Print Longest Increasing Subsequence
Ans. 
Print the longest increasing subsequence of an array of strings.
• Use dynamic programming to find the longest increasing subsequence.

• Iterate through the array and keep track of the longest increasing subsequence ending at each index.

• Return the longest increasing subsequence found.
Answered by AI
Add your answer

Round duration - 90 minutes
Round difficulty - Hard

They gave around 7 days of time for attending the test.
It had 4 coding questions out of which I solved 2 fully and 2 partially. 
Questions were medium-hard and based on DSA.

Q1. 
Find the Third Greatest Element
Given an array 'ARR' of 'N' distinct integers, determine the third largest element in the array.
Input:
The first line contains a single integer 'T' representing the numb...read more
Ans. 
Find the third largest element in an array of distinct integers.
• Sort the array in descending order and return the element at index 2.

• Handle cases where the array has less than 3 elements separately.

• Consider edge cases like negative integers and duplicates.
Answered by AI
Add your answer
Q2. 
Wildcard Pattern Matching Problem Statement
Implement a wildcard pattern matching algorithm to determine if a given wildcard pattern matches a text string completely.
The wildcard pattern may include the...read more
Ans. 
Implement a wildcard pattern matching algorithm to determine if a given wildcard pattern matches a text string completely.
• Create a recursive function to match the pattern with the text character by character.

• Handle cases for '?' and '*' characters in the pattern.

• Use dynamic programming to optimize the solution.

• Check for edge cases like empty pattern or text.
Answered by AI
Add your answer
Q3. 
Detect and Remove Loop in Linked List
For a given singly linked list, identify if a loop exists and remove it, adjusting the linked list in place. Return the modified linked list.
Expected Complexity:
A...read more
Ans. 
Detect and remove loop in a singly linked list with O(n) time complexity and O(1) space complexity.
• Use Floyd's Cycle Detection Algorithm to identify the loop in the linked list.

• Once the loop is detected, use two pointers to find the start of the loop.

• Adjust the pointers to remove the loop and return the modified linked list.

• Example: For input 5 2 and elements 1 2 3 4 5, output should be 1 2 3 4 5.
Answered by AI
Add your answer
Q4. 
Longest Common Subsequence Problem Statement
Given two strings STR1 and STR2, determine the length of their longest common subsequence.
A subsequence is a sequence that can be derived from another sequen...read more
Ans. 
The task is to find the length of the longest common subsequence between two given strings.
• Implement a function to find the longest common subsequence length.

• Use dynamic programming to solve the problem efficiently.

• Iterate through the strings to find the common subsequence.

• Handle edge cases like empty strings or equal strings.

• Example: For input 'abcde' and 'ace', the longest common subsequence is 'ace' with a length of
Answered by AI
Add your answer

Round duration - 50 minutes
Round difficulty - Medium

First round was a basic javascript problem-solving round. The interviewer judged my grasp on fundamental javascript concepts like objects, closures, polyfills, etc. It was during the afternoon and was conducted on google meet and leetcode playground.
The interviewer was very calm. I was first asked some general questions like why I'm applying for this role and what are the projects I've done.

Q1. 
Search in a Row-wise and Column-wise Sorted Matrix Problem Statement
You are given an N * N matrix of integers where each row and each column is sorted in increasing order. Your task is to find the positi...read more
Ans. 
This question asks to find the position of a target integer in a row-wise and column-wise sorted matrix.
• Iterate through each row and column of the matrix

• Compare the target integer with the current element

• If the target integer is found, return the position as {i, j}

• If the target integer is not found, return {-1, -1}
Answered by AI
Add your answer

Round duration - 40 minutes
Round difficulty - Easy

One DSA Question along with some javascript questions were asked like hoisting, difference between JSX and Javascript etc.

Q1. 
Trapping Rain Water Problem Statement
You are given a long type array/list ARR of size N, representing an elevation map. The value ARR[i] denotes the elevation of the ith bar. Your task is to determine th...read more
Ans. 
The question asks to find the total amount of rainwater that can be trapped in the given elevation map.
• Iterate through the array and find the maximum height on the left and right of each bar.

• Calculate the amount of water that can be trapped at each bar by taking the minimum of the maximum heights on the left and right.

• Sum up the trapped water for all bars and return the total amount.
Answered by AI
Add your answer