400+ HDFC Bank Interview Questions and Answers

Find the minimum cost to make all elements of an array equal by changing them to a common value.

• Calculate the median of the array and find the sum of absolute differences between each element and the median.

• Sort the array and find the median element, then calculate the sum of absolute differences between each element and the median.

• If the array has an even number of elements, consider the average of the two middle elements as the median.

The oldest pirate proposes to keep 98 coins for himself and give 1 coin to each of the other pirates.

• The oldest pirate will propose to keep the majority of the coins for himself to ensure the vote passes.

• The other pirates will vote in favor of the proposal to avoid being thrown overboard.

• The proposed distribution will be 98 coins for the oldest pirate and 1 coin for each of the other pirates.

Merge two sorted linked lists in-place to form a combined sorted linked list.

• Create a dummy node to start the merged list

• Compare nodes from both lists and link them accordingly

• Update the pointer to the next node in the merged list

• Handle cases where one list is longer than the other

• Return the head of the merged list

Add two numbers represented as linked lists and return the sum as a linked list.

• Traverse both linked lists simultaneously while keeping track of carry from previous sum

• Create a new linked list to store the sum of the two numbers

• Handle cases where one linked list is longer than the other by padding with zeros

• Update the current node with the sum of corresponding nodes from both lists and carry

The missing rupee is not actually missing. The calculation is misleading and does not account for the total amount paid.

• The initial amount paid by each person was Rs.10, totaling Rs.30.

• The owner gave them a discount of Rs.5, so they paid Rs.25 in total.

• The broker took Rs.2, leaving them with Rs.23.

• When the broker returned Rs.1 to each person, they each received Rs.1 back, totaling Rs.3.

• So, the total amount paid by the three friends is Rs.25 + Rs.3 = Rs.28.

• The remaining Rs.2 i...read more

The task is to find the next greater element for each element in an array to its right, if no greater element exists, return -1.

• Iterate through the array from right to left and use a stack to keep track of elements.

• Pop elements from the stack until a greater element is found or the stack is empty.

• Store the next greater element for each element in the output array.

The question asks to calculate 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 side of each bar.

• Calculate the amount of water that can be trapped on each bar by subtracting its height from the minimum of the maximum heights on both sides.

• Sum up the trapped water for all bars and return the total amount.

The task is to merge two sorted arrays into one sorted array.

• Create a new array with size M + N to store the merged array

• Use two pointers to iterate through the elements of ARR1 and ARR2

• Compare the elements at the current pointers and add the smaller element to the new array

• Move the pointer of the array from which the element was added

• Repeat the process until all elements are merged

• If there are remaining elements in ARR2, add them to the new array

• Return the merged array

Count the number of subarrays in an array whose elements have a bitwise XOR equal to a given value.

• Iterate through all subarrays and calculate the XOR value for each subarray.

• Keep track of the count of subarrays with XOR equal to the given value.

• Use a hashmap to store the XOR values encountered and their frequencies for efficient lookup.

• Handle edge cases like empty array or XOR value of 0 separately.

• Example: For input [4, 2, 2, 6] and XOR value 6, there are 2 subarrays [4, 2]...read more

Merge K sorted arrays into a single sorted array.

• Iterate through all arrays and merge them using a min-heap.

• Use a priority queue to efficiently merge the arrays.

• Time complexity can be optimized to O(N log K) using a min-heap.

Find the row with the maximum number of 1s in a sorted matrix.

• Iterate through each row of the matrix and count the number of 1s in each row

• Keep track of the row index with the maximum number of 1s

• Return the index of the row with the highest count of 1s

The height of a binary tree is the maximum number of edges from the root to a leaf node.

• Traverse the tree recursively and keep track of the maximum height

• If the current node is null, return 0

• Otherwise, calculate the height of the left and right subtrees and return the maximum height plus 1

Ask 'Which way would someone from the other city point to?'

• Ask the person which way they would point if they were from the other city

• If they are from the City of Truth, they would point towards the City of Truth

• If they are from the City of Lies, they would also point towards the City of Truth

Identify the longest palindromic substring in a given string.

• Iterate through the string and expand around each character to find palindromes

• Keep track of the longest palindrome found

• Return the longest palindrome with the smallest start index

Yes, the quick sort algorithm can be optimized to achieve NlogN complexity in the worst case by choosing the pivot element strategically.

• Choose the pivot element as the median of the first, middle, and last elements of the array to reduce the chances of worst-case scenarios.

• Implement a hybrid sorting algorithm that switches to a different sorting algorithm like insertion sort for small subarrays to improve efficiency.

• Randomize the selection of the pivot element to avoid predi...read more

Find the minimum sum path from a specified cell to the top left corner of a matrix.

• Use dynamic programming to keep track of the minimum sum at each cell

• Consider all possible moves (down, right, diagonal) from each cell

• Start from the specified cell and work towards the top left corner

• Add the value of the current cell to the minimum sum of the previous cells

The task is to determine if there exists a line parallel to the Y-axis that reflects given points symmetrically.

• Iterate through each test case and check if a vertical reflection line exists for the given points

• Calculate the midpoint of the x-coordinates and check if it reflects the points symmetrically

• Consider edge cases where points are on the reflection line or have the same x-coordinate

Use one candle as a timer and the other to measure 90 minutes.

• Light both candles at the same time.

• Let one candle burn for 30 minutes.

• Then light the other candle.

• When the second candle burns out, 90 minutes have passed.

• The first candle will have burned for 60 minutes, serving as a timer.

Find the maximum sum of a contiguous subarray within an array of integers.

• Iterate through the array and keep track of the maximum sum of subarrays seen so far.

• Use Kadane's algorithm to efficiently find the maximum subarray sum.

• Consider edge cases like all negative numbers in the array.

• Example: For input [-2, 1, -3, 4, -1], the maximum subarray sum is 4.

The man stood on a block of ice, which melted and caused him to hang himself.

• The man stood on a block of ice that was placed in the room.

• Over time, the block of ice melted, causing the man to hang himself.

• The length of the rope was initially longer than 3 ft, but as the ice melted, the rope became shorter.

• The water from the melted ice filled the room, making it wet.

The 0/1 Knapsack Problem involves maximizing profit by selecting items with specified weights and values within a knapsack's weight capacity.

• Create a 2D array to store the maximum profit that can be achieved at each weight capacity and item index.

• Iterate through each item and weight capacity, updating the maximum profit based on whether the item is included or not.

• Return the maximum profit achievable with the given items and weight capacity.

• Example: For N = 4, W = 10, weights...read more

The task is to determine if a given string consisting of parentheses is balanced or not.

• Iterate through the characters of the string and use a stack to keep track of opening parentheses.

• If an opening parenthesis is encountered, push it onto the stack.

• If a closing parenthesis is encountered, check if it matches the top of the stack. If it does, pop the stack, else the string is not balanced.

• At the end, if the stack is empty, the string is balanced.

• Example: For input '{}[]()', ...read more

Questions related to Salesforce Marketing Cloud features and functionalities.

• Data Extensions are tables that store data in Marketing Cloud, while Lists are simple collections of subscribers.

• A/B testing is a method of comparing two versions of a campaign to determine which one performs better.

• Data in Data Extensions can be filtered using SQL queries or Filter Activities in Automation Studio.

• Automation Studio Activities are pre-built actions that can be used to automate marketi...read more

Implement a stack using two queues to store integer values with specified functions.

• Use two queues to simulate stack operations efficiently.

• Maintain one queue for storing elements and another for temporary storage during push operation.

• Ensure to handle edge cases like empty stack and maximum size limit.

• Example: Push operation involves transferring elements from one queue to another before adding the new element.

• Example: Pop operation involves removing and returning the top el...read more

Reverse a given string containing alphabets, numbers, and special characters.

• Iterate through the string from the end to the beginning and append each character to a new string.

• Use built-in functions like reverse() or slicing to reverse the string.

• Handle special characters and numbers while reversing the string.

• Ensure to consider the constraints on the input string length and number of test cases.

Count substrings with exactly K distinct characters in a given lowercase string.

• Iterate through all substrings of the given string and count the number of distinct characters in each substring.

• Keep track of substrings with exactly K distinct characters and increment the count.

• Return the total count of substrings with exactly K distinct characters.

Generate a character pattern based on the input number of rows N, where each row starts with the i-th letter of the alphabet and contains i letters.

• Create an array to store each row of the pattern

• Iterate from 1 to N, for each row i, generate the string starting with the i-th letter of the alphabet and containing i letters

• Add each generated string to the array

• Return the array of strings as the output

Weighing 3 times is enough to find the odd ball out.

• Divide the balls into 3 groups of 3 each and weigh any 2 groups against each other.

• If they are equal, the odd ball is in the third group. Weigh 2 balls from that group to find the odd one.

• If they are not equal, the odd ball is in the heavier group. Weigh 2 balls from that group to find the odd one.

Find duplicate numbers in an unsorted array and return the array.

• Iterate through the array and keep track of seen numbers using a hash table.

• If a number is already in the hash table, it is a duplicate.

• Add the duplicate number to a new array and return it.

To reverse a string without using any looping and inbuilt functions, we can use recursion.

• Create a function that takes a string as input.

• If the length of the string is 0 or 1, return the string.

• Otherwise, call the function recursively with the substring starting from the second character and concatenate the first character at the end.

• Return the reversed string.

• Example: reverseString('hello') returns 'olleh'.

SSR and CSR websites refer to server-side rendering and client-side rendering respectively. SSR is used for better initial load performance and SEO, while CSR is suitable for dynamic and interactive content.

• SSR (Server-Side Rendering) websites render the web pages on the server and send the fully rendered HTML to the client.

• CSR (Client-Side Rendering) websites load a minimal HTML skeleton and then use JavaScript to fetch data and render the content on the client-side.

• SSR is b...read more

The probability of two ants colliding on an equilateral triangle is 1/3.

• Each ant has an equal chance of moving towards either of the other two ants.

• There are three possible scenarios where two ants can collide out of a total of nine possible scenarios.

• Therefore, the probability of two ants colliding is 1/3.

The ants will end up colliding at the centroid of the triangle.

• The ants will move towards each other in a straight line along the medians of the triangle.

• They will eventually meet at the centroid of the triangle, which is the point where all three medians intersect.

The limit for the number of arguments passed to functions is not fixed. Arrays or structures can be used to pass more parameters.

• The limit for the number of arguments passed to functions is not fixed and depends on the programming language and system architecture.

• In C programming language, there is no limit on the number of arguments that can be passed to a function.

• In Java, the maximum number of arguments that can be passed to a method is 255.

• To pass more parameters than the...read more

I would be ready to accept a project in Java even if I was trained in DotNet earlier.

• I have a strong foundation in programming principles and concepts, which can be applied to any language.

• I am confident in my ability to quickly learn and adapt to new technologies.

• I have experience working with multiple programming languages and frameworks.

• I can leverage my knowledge of DotNet to understand similar concepts in Java.

• I am motivated and enthusiastic about taking on new challenge...read more

By lighting both wires at the same time, the shorter wire will burn out first, allowing you to measure a specific duration of time.

• Light both wires at the same time

• Measure the time it takes for the shorter wire to burn out completely

• The remaining length of the longer wire will indicate the specific duration of time

Early binding is resolved at compile time, while late binding is resolved at runtime in C++.

• Early binding is also known as static binding, where the function call is resolved at compile time based on the type of the object.

• Late binding is also known as dynamic binding, where the function call is resolved at runtime based on the actual type of the object.

• Early binding is faster as the function call is directly mapped to the memory address at compile time.

• Late binding allows fo...read more

Clean Architecture is a software design principle that separates concerns and promotes testability, maintainability, and scalability.

• Clean Architecture emphasizes separation of concerns by dividing the codebase into layers: Presentation, Domain, and Data.

• Each layer has its own responsibilities and dependencies flow inward, ensuring loose coupling and high cohesion.

• The Presentation layer handles user interactions and UI components.

• The Domain layer contains business logic and u...read more

Use an auxiliary stack to keep track of minimum element at each level of the main stack.

• Create an auxiliary stack to keep track of minimum element at each level of the main stack.

• When pushing an element onto the main stack, compare it with the top element of the auxiliary stack and push the smaller one onto the auxiliary stack.

• When popping an element from the main stack, also pop the top element from the auxiliary stack.

• The top element of the auxiliary stack will always be th...read more

Connect 9 points in a 3x3 square using 4 lines without lifting the pen.

• Start at any point and draw a line to the adjacent point

• Continue drawing lines until all points are connected

• Make sure the lines intersect to form a square

To accommodate a CR in agile, the business analyst should follow a process that includes evaluating the impact, prioritizing, estimating effort, and incorporating the change into the sprint.

• Evaluate the impact of the change request on the project scope, timeline, and resources.

• Prioritize the change request based on its urgency and importance.

• Estimate the effort required to implement the change and communicate it to the stakeholders.

• Discuss the change request with the developm...read more

A priority queue can be implemented using a single queue or multiple queues.

• One approach is to use a single queue and assign priorities to elements using a separate data structure.

• Another approach is to use multiple queues, each representing a different priority level.

• For example, if there are three priority levels, three queues can be used to implement the priority queue.

The interview questions cover OOP concepts, coding exercises, project frameworks, Selenium automation, BDD with Cucumber, and TestNG.

• OOP concepts include inheritance, encapsulation, polymorphism, and abstraction.

• Example: Inheritance - a class 'Car' can inherit properties from a class 'Vehicle'.

• To find missing number in a list, iterate through the list and check for gaps in sequence.

• Example: List {1, 2, 4, 5} - Missing number is 3.

• To count alphabets in a string, iterate throug...read more

The treasure is in the red pot.

• The statement 'only one of the statement is correct' means that one statement is true and the other is false.

• If the blue pot has the treasure, then both statements would be true, which contradicts the given information.

• Therefore, the statement 'Blue pot has the treasure' must be false, and the treasure must be in the other pot, which is the red pot.

Diamond Problem is a common issue in multiple inheritance in C++ where a class inherits from two classes that have a common base class.

• Diamond Problem occurs when a class inherits from two classes that have a common base class, leading to ambiguity in accessing members.

• It can be resolved in C++ using virtual inheritance, where the common base class is inherited virtually to avoid duplicate copies of base class members.

• Example: class A is inherited by classes B and C, and then...read more

Different meetings in Agile style development include daily stand-up, sprint planning, sprint review, and retrospective.

• Daily stand-up: A short daily meeting where team members discuss their progress, plans, and any obstacles.

• Sprint planning: A meeting at the beginning of each sprint to determine the work to be done and set priorities.

• Sprint review: A meeting at the end of each sprint to demonstrate completed work to stakeholders and gather feedback.

• Retrospective: A meeting a...read more

An array of objects can be used to implement a heterogeneous array.

• Each element in the array can be an object that represents a different data type.

• The objects can have different properties and methods based on their respective data types.

• For example, an element can be an object representing a string with a 'value' property and a 'length' method.

Levels of data abstraction in a DBMS refer to the different views of data provided to users and applications.

• Physical level: Deals with how data is stored on the storage media. Example: data blocks, pages, indexes.

• Logical level: Focuses on how data is represented to users. Example: tables, views, constraints.

• View level: Provides a customized view of the database for specific users or applications. Example: queries, reports.

It would take a maximum of 3 trials to figure out the hollow ball.

• Divide the balls into 3 groups of 3 balls each.

• Weigh 2 groups against each other. If one group is lighter, move to next step.

• Weigh 2 balls from the lighter group. The lighter ball is the hollow one.

If a job fails in the pipeline and data processing cycle is over, it can lead to incomplete or inaccurate data.

• Incomplete data may affect downstream processes and analysis

• Data quality may be compromised if errors are not addressed

• Monitoring and alerting systems should be in place to detect and handle failures

• Re-running the failed job or implementing error handling mechanisms can help prevent issues in the future

The duration of a sprint is typically 2-4 weeks and it is led by the Scrum Master or Agile Coach.

• A sprint is a time-boxed iteration in Agile development.

• The duration of a sprint is determined by the team, but it is usually between 2-4 weeks.

• During a sprint, the team works on a set of prioritized user stories or tasks.

• The Scrum Master or Agile Coach is responsible for leading the sprint and ensuring that the team follows the Agile principles and practices.

• They facilitate the s...read more

Stakeholders are individuals or groups who have an interest or influence in a project or organization.

• Stakeholders can include employees, customers, suppliers, shareholders, government agencies, and community members.

• They can be classified into internal stakeholders (e.g., employees, shareholders) and external stakeholders (e.g., customers, suppliers).

• Stakeholders can also be categorized based on their level of influence or interest in the project.

• Some stakeholders may have h...read more

Data abstraction is the process of hiding the implementation details of a data structure and only showing the necessary information to the user.

• Data abstraction can be achieved through the use of abstract classes and interfaces in object-oriented programming.

• It helps in reducing complexity by providing a simplified view of the data.

• Example: In Java, abstract classes and interfaces are used to achieve data abstraction.

• Example: Encapsulation is another technique used to achieve...read more

Static variables have local scope but retain their value between function calls, while global variables have global scope.

• Static variables are declared inside a function and retain their value between function calls

• Global variables are declared outside of any function and can be accessed from any part of the program

• Static variables have local scope, while global variables have global scope

• Static variables are initialized only once, while global variables are initialized at th...read more

if else is used for simple conditions while switch case is used for multiple conditions.

• if else is a sequential decision-making statement while switch case is a multi-branch decision-making statement

• if else is used when there are only a few conditions to be checked while switch case is used when there are multiple conditions to be checked

• if else can have multiple conditions in a single statement while switch case can only have one condition per case

• if else is more readable an...read more

Various documents are created during the business analysis process.

• Business requirements document (BRD)

• Functional requirements document (FRD)

• Use case document

• Process flow diagrams

• Data flow diagrams

• User stories

• Test plans

• Training materials

• Project charter

• Risk assessment document

Garbage collector identifies objects to pick based on their reachability.

• Garbage collector starts from a set of root objects and identifies all objects that are reachable from them.

• Objects that are not reachable are considered garbage and are eligible for collection.

• Reachability is determined by following object references from root objects.

• Objects that are referenced by other reachable objects are also considered reachable.

• Objects that are not referenced by any reachable obj...read more

You will use the scale 2 times to determine which ball is defective.

• First, divide the 8 balls into 3 groups - 3 balls, 3 balls, and 2 balls.

• Weigh the first two groups of 3 balls against each other. If they balance, the defective ball is in the group of 2 balls.

• If one group of 3 balls is lighter, weigh two of those balls against each other. If they balance, the defective ball is the third ball.

• If one group of 3 balls is heavier, weigh two of those balls against each other. The...read more

ACID properties in DBMS ensure data integrity and consistency in transactions.

• Atomicity: All operations in a transaction are completed successfully or none at all.

• Consistency: Data is always in a valid state before and after a transaction.

• Isolation: Transactions are isolated from each other to prevent interference.

• Durability: Once a transaction is committed, changes are permanent and survive system failures.

• Example: If a bank transfer involves debiting one account and crediti...read more

Create a Login form with email validation using Vanilla JS.

• Create a form in HTML with input fields for email and password

• Use JavaScript to validate the email input using regular expressions

• Display error messages if the email input is not in the correct format

FRD and BRD are both documents used in the software development process, but they serve different purposes.

• FRD stands for Functional Requirements Document and describes the functional requirements of a software system.

• BRD stands for Business Requirements Document and outlines the business needs and objectives that the software system should fulfill.

• FRD focuses on the specific functionalities and features of the software, while BRD focuses on the overall business goals and req...read more

C++ is an extension of C with object-oriented programming features.

• C++ supports classes and objects while C does not.

• C++ has better support for polymorphism and inheritance.

• C++ has a standard template library (STL) which C does not have.

• C++ allows function overloading while C does not.

• C++ has exception handling while C does not.

System diagram for e-commerce order placement and history retrieval

• Frontend: Customer interface for browsing products, adding to cart, and placing orders

• Backend: Order processing system to handle order placement, payment processing, and order fulfillment

• Database: Store customer information, order details, and order history for retrieval

• APIs: Communication between frontend, backend, and database for seamless order processing

• Analytics: Track order history and customer behavior ...read more

Remove duplicates from a list of objects.

• Create a new empty list.

• Iterate through the original list.

• For each object, check if it is already in the new list.

• If not, add it to the new list.

• Return the new list without duplicates.

For loop is used for iterating over a sequence while while loop is used for iterating until a condition is met.

• For loop is used when the number of iterations is known beforehand

• While loop is used when the number of iterations is not known beforehand

• For loop is faster than while loop for iterating over a sequence

• While loop is useful for iterating until a specific condition is met

• For loop can be used with range() function to iterate over a sequence

• While loop can be used with br...read more

To enhance web performance of a page, optimize images, minify code, reduce server response time, use caching, and enable compression.

• Optimize images by compressing them and using appropriate file formats.

• Minify code by removing unnecessary characters and whitespace.

• Reduce server response time by using a content delivery network (CDN) and optimizing database queries.

• Use caching to store frequently accessed data and reduce server requests.

• Enable compression to reduce file sizes...read more

Lists and tuples are both data structures in Python, but lists are mutable while tuples are immutable. OOP concepts include inheritance, encapsulation, and polymorphism. Decorators are used to modify functions or methods. Lambda functions are anonymous functions. Reduce, filter, generators, and iter objects are all related to functional programming in Python.

• Lists are mutable, meaning they can be changed after creation. Tuples are immutable, meaning they cannot be changed aft...read more

10 plants can be planted in 5 rows with 4 plants in each row.

• Divide the plants into groups of 4.

• Arrange the groups in 5 rows.

• Each row will have 4 plants.

Code can be verified before compile time using static code analysis tools.

• Static code analysis tools can detect potential bugs, security vulnerabilities, and coding errors before compilation.

• Examples of static code analysis tools include SonarQube, Checkstyle, and PMD.

• These tools can be integrated into the development process to ensure code quality and reduce the risk of errors.

• Static code analysis can also help enforce coding standards and best practices.

• Regular use of stati...read more

Function definition specifies the implementation of a function, while declaration provides the function signature.

• Function definition includes the function body, while declaration only includes the function signature.

• Function definition is used to define the behavior of a function, while declaration is used to announce the existence of a function.

• Function definition can only appear once in a program, while declaration can appear multiple times.

• Example of function definition: ...read more

Three steps for using functions in C.

• Declare the function with its return type, name, and parameters.

• Define the function by writing the code for it.

• Call the function by using its name and passing arguments if necessary.

A stack is a data structure that follows the Last In First Out (LIFO) principle.

• Push: adds an element to the top of the stack

• Pop: removes the top element from the stack

• Peek: returns the top element without removing it

• IsEmpty: checks if the stack is empty

• Size: returns the number of elements in the stack

Method overloading is having multiple methods with the same name but different parameters. Method overriding is having a subclass method with the same name and parameters as a superclass method.

• Method overloading is used to provide different ways of calling the same method with different parameters.

• Method overriding is used to provide a specific implementation of a method in a subclass that is already defined in the superclass.

• Method overloading is resolved at compile-time ba...read more

Switch case is used for multiple conditions while if else is used for binary conditions.

• Switch case is faster than if else for multiple conditions.

• If else can handle complex conditions while switch case cannot.

• Switch case can only compare values of the same data type.

• If else can handle null values while switch case cannot.

• Example: switch (day) { case 1: console.log('Monday'); break; case 2: console.log('Tuesday'); break; default: console.log('Invalid day'); }

• Example: if (age ...read more

Sorting a list of strings based on their occurrence count.

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

• Use the dictionary to sort the list based on the count of occurrences.

• If two strings have the same count, sort them alphabetically.

• Return the sorted list.

Swapping numbers without using a temporary variable

• Use addition and subtraction to swap the numbers

• Example: a = 5, b = 10. a = a + b (15), b = a - b (5), a = a - b (10)

• Alternatively, use bitwise XOR operation to swap the numbers

• Example: a = 5, b = 10. a = a ^ b (15), b = a ^ b (5), a = a ^ b (10)