Citicorp Lead Software Engineer Interview Questions and Answers

Find an odd occurring number among even occurring numbers.

• Use XOR operation to cancel out even occurring numbers and get the odd occurring number.

• Iterate through the array and XOR each element with the result variable.

• The final result will be the odd occurring number.

Print the spiral order of a binary tree and matrix.

• For binary tree, use level order traversal and alternate direction for each level.

• For matrix, use four pointers to traverse in spiral order.

• Example for binary tree: 1 -> 2 -> 3 -> 4 -> 5 -> 6 -> 7 -> 8 -> 9

• Example for matrix: 1 2 3 4 -> 8 7 6 5 -> 9 10 11 12 -> 16 15 14 13

Finding pairs in an array with a given sum.

• Iterate through the array and for each element, check if the difference between the given sum and the element exists in the array.

• Use a hash table to store the elements of the array and their indices for faster lookup.

• If there are multiple pairs with the same sum, return any one of them.

• If no pair is found, return null or an empty array.

Find total number of k element with given avg in an array in minimum time complexity.

• Use sliding window technique to traverse the array in O(n) time complexity.

• Maintain a sum variable to keep track of the sum of elements in the window.

• If the sum of elements in the window is equal to k times the given avg, increment the count.

• Move the window by subtracting the first element and adding the next element in the array.

Printing non-boundary elements of a binary tree

• Traverse the tree in any order (preorder, inorder, postorder)

• Check if the current node is not a boundary node (not the first or last node in its level)

• If it is not a boundary node, print its value

• Recursively traverse its left and right subtrees

Yes, the string class can be extended in most programming languages.

• Inheritance can be used to extend the functionality of the string class.

• By creating a new class that inherits from the string class, additional methods and properties can be added.

• Extending the string class allows for customization and adding specific functionality to strings.

• Example: In Python, the string class can be extended by creating a new class

Implicit objects in JSP are predefined objects that are available for use without any declaration or initialization.

• Implicit objects in JSP include request, response, session, application, out, config, pageContext, page, exception, and others.

• These objects provide access to various aspects of the JSP environment and can be used to perform common tasks.

• For example, the request object allows access to HTTP request parame...read more

A hash map is a data structure that uses a hash function to map keys to values.

• Hash map stores key-value pairs

• It uses a hash function to compute an index for each key

• Collisions can occur when two keys hash to the same index

• Hash maps provide fast access to values based on their keys

StringBuffer and StringBuilder are both used to manipulate strings, but StringBuffer is thread-safe while StringBuilder is not.

• StringBuffer is synchronized, making it safe for use in multi-threaded environments.

• StringBuilder is not synchronized, making it faster but not thread-safe.

• StringBuffer is preferred when multiple threads are involved, while StringBuilder is preferred for single-threaded scenarios.

• Both classes p...read more

MVC is a software architectural pattern that separates an application into three main components: Model, View, and Controller.

• Model represents the data and business logic of the application.

• View is responsible for displaying the user interface.

• Controller handles user input, updates the model, and interacts with the view.

• MVC promotes separation of concerns and modularity in software development.

• Example: In a web applica...read more

Annotations used in RESTful web services

• 1. @Path - Specifies the URI path for the resource

• 2. @GET - Specifies that the method handles HTTP GET requests

• 3. @POST - Specifies that the method handles HTTP POST requests

• 4. @PUT - Specifies that the method handles HTTP PUT requests

• 5. @DELETE - Specifies that the method handles HTTP DELETE requests

• 6. @PathParam - Binds the value of a URI template parameter to a method paramete...read more

I have a strong background in software engineering and a passion for innovation, making me a valuable asset to HSBC.

• I have a proven track record of successfully delivering high-quality software solutions in previous roles.

• I am highly skilled in various programming languages and technologies, including Java, Python, and SQL.

• I have experience working in agile development environments, allowing me to adapt quickly to chan...read more

Multi tasking, multi processing, and multi programming are different approaches to managing tasks in an operating system.

• Multi tasking allows multiple tasks to run concurrently on a single processor.

• Multi processing involves multiple processors running tasks simultaneously.

• Multi programming allows multiple programs to be loaded into memory and executed concurrently.

• Examples of multi tasking operating systems include Wi...read more

Memory allocation refers to the process of assigning memory to programs during runtime.

• Stack allocation is done automatically and is limited in size.

• Heap allocation is done manually and is larger in size.

• Stack memory is used for local variables and function calls.

• Heap memory is used for dynamic memory allocation.

• Memory leaks can occur if heap memory is not properly managed.

Use a shared variable and synchronization mechanisms to ensure natural order printing of numbers.

• Create two threads, one for printing even numbers and the other for printing odd numbers.

• Use a shared variable to keep track of the current number to be printed.

• Implement synchronization mechanisms like locks or semaphores to ensure only one thread can access the shared variable at a time.

• Each thread should check if it is i...read more

Printing a matrix in spiral order

• Start from the first element and print it

• Move in a spiral order towards the center of the matrix

• Repeat until all elements are printed

Thread class and Runnable Interface are used for multithreading in Java.

• Thread class is a predefined class in Java that provides methods to create and control threads.

• Runnable interface is used to define a task that can be executed by a thread.

• Thread class implements Runnable interface.

• Thread class provides more control over threads than Runnable interface.

• Example: Thread t = new Thread(new MyRunnable()); t.start();

• Exa...read more

Linked List is a dynamic data structure while ArrayList is a static data structure.

• Linked List is best for frequent insertion and deletion operations.

• ArrayList is best for frequent access operations.

• Linked List uses more memory than ArrayList.

• ArrayList is faster than Linked List for accessing elements.

• Use Linked List when you need to frequently add or remove elements from the list.

• Use ArrayList when you need to frequen

I am not interested in a career in investment banking.

• I am more interested in a career in software development

• I enjoy problem-solving and creating innovative solutions through coding

• Investment banking does not align with my passion and skill set

I have chosen to apply to J.P. Morgan because of their reputation, global presence, and opportunities for growth.

• J.P. Morgan has a strong reputation in the financial industry.

• They have a global presence with offices in multiple countries.

• The company offers various opportunities for career growth and development.

• J.P. Morgan is known for its innovative technology solutions in the financial sector.

• I am impressed by their ...read more

Yes, I have made a mistake in my previous project.

• I underestimated the complexity of a task and ended up missing the deadline.

• I failed to properly test a feature, resulting in a bug that affected user experience.

• I accidentally deleted an important file without having a backup.

• I misunderstood a requirement and implemented a feature incorrectly.