HomeShop18 Senior QA Engineer Interview Questions and Answers

A program to swap two pointers.

• Declare two pointers of the same data type

• Assign the first pointer to a temporary variable

• Assign the second pointer to the first pointer

• Assign the temporary variable to the second pointer

Dijkstra's algorithm finds shortest path between nodes in a graph

• Create a graph with nodes and edges

• Initialize distances from source node to all other nodes as infinity

• Set distance from source node to itself as 0

• Create a set of unvisited nodes

• While unvisited set is not empty, select node with minimum distance

• For each neighbor of selected node, calculate distance from source node

• If calculated distance is less than curre...read more

Floyd-Warshall's algorithm is used to find the shortest path between all pairs of vertices in a weighted graph.

• Create a 2D array to store the distances between all pairs of vertices.

• Initialize the array with the weights of the edges in the graph.

• Use nested loops to iterate over all pairs of vertices and update the distances if a shorter path is found through a third vertex.

• The final array will contain the shortest dist

Program to print matrix elements in spiral order recursively

• Create a recursive function to print the elements in spiral order

• Define the boundaries of the matrix and traverse the matrix in spiral order

• Call the recursive function to print the elements in spiral order

• Handle edge cases such as empty matrix or matrix with only one row/column

Find two numbers in an unsorted array that add up to a given sum in O(n)

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

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

• If it is, return the current element and the corresponding difference

• If not, add the current element to the hash table

Indexing is a technique used in DBMS to improve the performance of queries.

• Indexing creates a separate data structure that allows faster retrieval of data.

• It works by creating a pointer to the location of data in the table.

• Indexes can be created on one or more columns of a table.

• Types of indexing include B-tree, hash, and bitmap indexing.

• Indexes can also be clustered or non-clustered.

• Clustered indexes determine the phy...read more

B and B+ trees are data structures used for efficient searching and sorting of large datasets.

• B trees are balanced trees used for disk-based storage systems.

• B+ trees are similar to B trees but have all data stored in the leaf nodes for faster searching.

• B trees have a variable number of keys per node, while B+ trees have a fixed number.

• B trees have a higher fanout than B+ trees, making them more efficient for smaller da...read more

Program to find lowest common ancestor of two nodes in binary search tree and binary tree with brute force approach.

• For binary search tree, traverse from root to both nodes and store the path. Then compare paths to find LCA.

• For binary tree, traverse from root to both nodes and store the path. Then compare paths to find LCA.

• Brute force approach involves checking each node's descendants to see if they contain both nodes.

• ...read more

Program to print all ancestors of a node in a binary tree

• Create a recursive function to traverse the binary tree

• Check if the current node is the target node

• If yes, print all the nodes in the call stack

• If not, recursively call the function for left and right subtrees

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

Calculate the level sum of a binary tree.

• Traverse the tree level by level using BFS

• Add the values of nodes at each level

• Store the level sum in an array

• Return the array of level sums

Vertical sum of binary tree is the sum of all nodes in each vertical line of the tree.

• Traverse the tree in-order and keep track of the horizontal distance of each node from the root.

• Use a hash table to store the sum of nodes at each horizontal distance.

• Recursively traverse the left and right subtrees and update the hash table accordingly.

Calculate top 10 frequently used words on Facebook in 1 hour dynamically.

• Use Facebook API to fetch data

• Implement a script to count word frequency

• Sort the words based on frequency and return top 10

I am a software engineer with experience in developing web applications and a passion for problem-solving.

• Proficient in programming languages such as Java, Python, and JavaScript

• Experience with front-end frameworks like React and Angular

• Familiarity with back-end technologies such as Node.js and Spring Boot

• Strong understanding of data structures and algorithms

• Ability to work collaboratively in a team environment

There are 204 squares and 1296 rectangles on a standard 8x8 chess board.

• The number of squares can be calculated using the formula n(n+1)(2n+1)/6, where n is the number of rows/columns.

• The number of rectangles can be calculated using the formula n(n+1)m(m+1)/4, where n and m are the number of rows and columns respectively.

• For an 8x8 chess board, there are 64 squares of size 1x1, 49 squares of size 2x2, 36 squares of siz...read more

An immutable class is a class whose instances cannot be modified after creation.

• Make all fields private and final

• Don't provide any setter methods

• Ensure that any mutable objects passed to the constructor are defensively copied

• Make the class final so that it cannot be subclassed

Singleton pattern ensures only one instance of a class is created and provides a global point of access to it.

• Create a private constructor to prevent direct instantiation of the class.

• Create a private static instance of the class.

• Create a public static method to access the instance, and create the instance if it doesn't exist.

• Ensure thread safety by using synchronized keyword or double-checked locking.

Vector is synchronized and ArrayList is not. Vector is thread-safe and ArrayList is not.

• Vector is a legacy class and ArrayList is a part of the Java Collection Framework.

• Vector is synchronized which means only one thread can access it at a time, while ArrayList is not.

• Vector is thread-safe which means it can be used in a multi-threaded environment, while ArrayList is not.

• Vector is slower than ArrayList because of synch...read more

Create Linked List without using internal library and provide add, delete, find functionality.

• Create a Node class with data and next pointer

• Create a LinkedList class with head pointer and methods to add, delete, and find nodes

• Use a loop to traverse the list and perform operations

• Handle edge cases such as adding to an empty list or deleting the head node

The current system follows a microservices architecture.

• The system is divided into multiple independent services.

• Each service has its own database and communicates with other services through APIs.

• The architecture allows for scalability and flexibility.

• Examples of microservices used in the system include user authentication, payment processing, and inventory management.

Find the total no of islands in a 2D matrix.

• Use DFS or BFS to traverse the matrix.

• Mark visited cells to avoid repetition.

• Count the number of islands found.

Loop detection in a linked list.

• Use two pointers, one moving at twice the speed of the other.

• If there is a loop, the faster pointer will eventually catch up to the slower one.

• If there is no loop, the faster pointer will reach the end of the list.