Text Mercato Information Technology Support Engineer Interview Questions and Answers

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.

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