Zepto Principal Engineer Interview Questions and Answers

Boundary traversal of a tree is the process of visiting the nodes on the boundary of a tree in a specific order.

• The boundary traversal can be done in three steps: left boundary, leaf nodes, and right boundary.

• For the left boundary, start from the root and traverse down the left side of the tree until reaching a leaf node.

• For the leaf nodes, perform an inorder traversal to visit all the leaf nodes of the tree.

• For the ri...read more

Find the nearest greater value of a given value in a Binary Search Tree (BST).

• Start from the root node and compare the given value with the current node's value.

• If the given value is less than the current node's value, move to the left subtree.

• If the given value is greater than the current node's value, move to the right subtree.

• Keep track of the closest greater value encountered while traversing the tree.

• Return the cl

Given an infinite staircase with a broken kth step, find the maximum height we can reach in n rounds of jumping i steps.

• We can start by jumping the maximum number of steps in each round until we reach the broken step.

• After reaching the broken step, we can discard the i steps that would land us on the broken step and jump the remaining steps.

• We can continue this pattern until we reach the maximum height we can reach wit

Function to check if a string of parenthesis is balanced

• Use a stack to keep track of opening parenthesis

• If a closing parenthesis is encountered, pop from stack and check if it matches

• If stack is empty and a closing parenthesis is encountered, return False

• If all parenthesis are matched and stack is empty, return True

Count the occurrences of words in a paragraph.

• Split the paragraph into words using whitespace as a delimiter.

• Create a dictionary to store the count of each word.

• Iterate through the words and increment the count in the dictionary.

• Return the dictionary with the word counts.

Find common elements out of two sorted array

• Use two pointers to traverse both arrays simultaneously

• Compare elements at each pointer and move the pointer of the smaller element

• If elements are equal, add to common elements list and move both pointers

• Stop when either pointer reaches end of array

Convert a Binary Search Tree to a Doubly Linked List.

• Create a DLL node class with left, right, and data fields.

• Traverse the BST in-order and add each node to the DLL.

• Adjust the left and right pointers of each node to create the DLL.

• Return the head of the DLL.

The task is to fill the 'next' field of each node in a binary tree to point to the next node at the same level.

• Use a level order traversal to process the tree nodes.

• Maintain a queue to store the nodes at each level.

• For each node, set its 'next' field to the next node in the queue.

• If a node is the last node at its level, set its 'next' field to NULL.

To find anagrams of a given word in a dictionary, use a hash table to store sorted versions of each word as keys and their corresponding original words as values.

• Create a hash table to store the anagrams

• Iterate through each word in the dictionary

• Sort the characters of the word and use it as a key in the hash table

• If the key already exists, add the word to the list of values for that key

• Print the list of values for the

Suggest a data structure for efficient search of a string in 10 files and print line number and file if string appears more than once.

• Use a hash table to store the file name and line number of each occurrence of the string.

• Iterate through each file and for each line, check if the string is present and update the hash table accordingly.

• Print the hash table entries for the string.

Amazon is the right place for me because of its innovative culture, vast resources, and opportunities for growth.

• Amazon's innovative culture aligns with my passion for pushing boundaries and finding creative solutions.

• The company's vast resources provide the necessary tools and support to develop and deliver high-quality software.

• Amazon offers numerous opportunities for growth and career advancement, allowing me to con...read more

I am a passionate software engineer with experience in developing web applications and a strong background in computer science.

• Experienced in developing web applications using technologies such as HTML, CSS, JavaScript, and React

• Strong background in computer science with knowledge of data structures and algorithms

• Proficient in programming languages such as Java, Python, and C++

• Familiar with Agile development methodolog

Flipkart is a leading e-commerce platform in India with a strong focus on technology and innovation.

• Flipkart offers a challenging and dynamic work environment for software engineers.

• The company has a strong reputation for investing in technology and innovation.

• Flipkart has a large user base and offers opportunities to work on a variety of projects.

• The company has a strong focus on customer satisfaction and user experie...read more

Yes, I am comfortable with reallocating as needed.

• I am flexible and adaptable to changing circumstances.

• I have experience working in dynamic environments where priorities can shift.

• I am willing to take on new challenges and responsibilities as required.

I have a strong technical background, excellent problem-solving skills, and a proven track record of delivering high-quality software.

• Extensive experience in software development, including proficiency in multiple programming languages such as Java, Python, and C++

• Strong problem-solving skills demonstrated through successful completion of complex projects

• Proven track record of delivering high-quality software on time a...read more

Implementing a shuffle function for a playlist of songs

• Create a new empty playlist

• Randomly select a song from the original playlist and add it to the new playlist

• Remove the selected song from the original playlist

• Repeat until all songs have been added to the new playlist

• Return the new shuffled playlist

Memory leak is a situation where a program fails to release memory it no longer needs.

• Memory leaks can cause a program to consume more and more memory over time, eventually leading to crashes or other issues.

• Memory leaks can be caused by programming errors such as not freeing memory after it is no longer needed.

• Tools like valgrind can be used to detect memory leaks in C and C++ programs.

• Examples of memory leaks include...read more

Arrays have fixed size and can lead to memory wastage and performance issues.

• Arrays have a fixed size and cannot be resized dynamically.

• Inserting or deleting elements in an array can be time-consuming.

• Arrays can lead to memory wastage if they are not fully utilized.

• Arrays can cause performance issues if they are too large and need to be traversed frequently.

• Arrays can also be prone to buffer overflow attacks.

• Example: A...read more

Function to hide text on mouse click in JavaScript

• Create a function that takes an element as input

• Add an event listener to the element for a mouse click

• Toggle the element's display property between 'none' and its original value

Find two elements in an unsorted array whose sum is equal to a given number x.

• Use a hash table to store the difference between x and each element in the array.

• Iterate through the array and check if the current element is in the hash table.

• Return the pair of elements that add up to x.

BST stands for Binary Search Tree, a data structure used for efficient searching and sorting operations.

• BST is a tree-like data structure where each node has at most two children.

• The left child of a node contains a value less than the parent node, while the right child contains a value greater than the parent node.

• BST allows for efficient searching and sorting operations with a time complexity of O(log n).

• Examples of a...read more

Number of possible BSTs with 2 and 3 nodes.

• For 2 nodes, only 2 BSTs are possible.

• For 3 nodes, 5 BSTs are possible.

• Number of BSTs can be calculated using Catalan numbers formula.

• Catalan(2) = 2, Catalan(3) = 5.

Answering the question about possible trees with two and three nodes.

• For two nodes, there is only one possible tree.

• For three nodes, there are three possible trees.

• The formula for calculating the number of possible trees with n nodes is (2n-3)!!.

• The double exclamation mark represents the double factorial function.

• The double factorial function is defined as n!! = n(n-2)(n-4)...(1 or 2).

B+ trees are balanced trees used for indexing and searching large amounts of data.

• B+ trees are similar to binary search trees but have multiple keys per node.

• They are commonly used in databases and file systems.

• B+ trees have a high fanout, reducing the number of disk accesses required for searching.

• They are also self-balancing, ensuring efficient performance even with large amounts of data.

• Example: In a database, a B+ ...read more

Yes, I have a few questions.

• Can you tell me more about the team I'll be working with?

• What is the company culture like?

• What are the biggest challenges the team is currently facing?

• Can you walk me through the development process for a typical project?

• What opportunities are there for professional growth and development?

I prefer hash tables for their constant time lookup and insertion.

• Hash tables are efficient for storing and retrieving data.

• They have constant time complexity for both insertion and lookup.

• They can be implemented using arrays or linked lists.

• Examples include Python's dictionary and Java's HashMap.

Yes, we can implement a stack using two queues.

• Push operation: Enqueue the element to the first queue.

• Pop operation: Dequeue all elements from the first queue and enqueue them to the second queue until the last element. Dequeue and return the last element. Swap the names of the queues.

• Top operation: Same as pop operation but don't dequeue the last element.

• Example: Push 1, 2, 3. Queue 1: 1 2 3. Queue 2: empty. Pop opera...read more

Find minimum no of platforms required to avoid collision between trains based on their arrival and departure times.

• Sort both arrays in ascending order

• Initialize platform count and max count to 1

• Loop through both arrays and compare arrival and departure times

• If arrival time is less than or equal to departure time, increment platform count

• Else, decrement platform count

• Update max count if platform count is greater than ma

JVM stands for Java Virtual Machine. It is an abstract machine that provides a runtime environment for Java programs.

• JVM is responsible for interpreting the compiled Java code and executing it.

• It provides platform independence by converting bytecode into machine-specific code.

• JVM has various components like class loader, bytecode verifier, and execution engine.

• Compiler converts source code into bytecode, while JVM exec...read more

I am a software engineer with experience in developing web applications and a passion for learning new technologies.

• Experienced in developing web applications using technologies such as Java, Spring, and Angular

• Passionate about learning new technologies and keeping up with industry trends

• Strong problem-solving skills and ability to work in a team environment

• Completed a Bachelor's degree in Computer Science from XYZ Uni

PayTM is an Indian e-commerce payment system and digital wallet company.

• PayTM was founded in 2010 by Vijay Shekhar Sharma.

• It started as a mobile recharge and bill payment platform.

• PayTM has expanded to offer services like online shopping, movie ticket booking, and travel bookings.

• It also offers a digital wallet that can be used to pay for various services and products.

• PayTM has over 350 million registered users and is ...read more

I would like to add a feature for splitting bills among friends.

• The feature would allow users to split bills for movies, dinners, etc.

• Users can select friends from their contact list and split the bill equally or unequally.

• The app would send a notification to the selected friends to pay their share.

• The feature would make it easier for users to split expenses and avoid awkward conversations.

• It would also encourage more

My favourite app is Spotify. I would like to see improvements in the algorithm for personalized playlists.

• Improved algorithm for personalized playlists

• Better integration with social media platforms

• Option to create collaborative playlists with friends

My favourite subject is Computer Science.

• I enjoy programming and problem-solving.

• I find algorithms and data structures fascinating.

• I am interested in artificial intelligence and machine learning.

• I like learning about new technologies and keeping up with industry trends.

I choose NIT Hamirpur because of its excellent academic reputation and beautiful campus.

• NIT Hamirpur has a strong focus on academics and research, which aligns with my career goals.

• The campus is located in a serene and picturesque location, which provides a conducive environment for learning.

• The faculty members are highly experienced and knowledgeable, and are always willing to help students.

• The college has state-of-th...read more