20+ Nykaa Interview Questions and Answers

A javascript function to find the maximum and minimum occurrence of a letter in a string.

• Create an object to store the count of each letter in the string

• Loop through the string and update the count in the object

• Find the maximum and minimum count in the object and return the corresponding letters

Sort a list of cards based on their rank and suit.

• Create a custom sorting function that first sorts by rank and then by suit

• Use a comparison function to compare ranks and suits of each card

• Example: ['2H', '3D', '10S', 'AH', '4C'] should be sorted as ['2H', '3D', '4C', '10S', 'AH']

Merge two sorted lists with n+m complexity

• Create a new list to store the merged result

• Iterate through both lists simultaneously and compare elements

• Add the smaller element to the new list and move to the next element in that list

• Continue until all elements from both lists are merged

A program to split an array of strings into smaller arrays based on a given split size.

• Iterate through the array and create a new subarray every split size elements

• Use array slicing or a loop to extract the subarrays

• Handle cases where the split size is larger than the array length

Program to flatten multi dimension Object[] array to Integer[]

• Use recursion to iterate through the array and flatten each element

• Check if each element is an array or an integer

• If it's an array, recursively flatten it

• If it's an integer, add it to the result array

Group by in Java stream based on 2 fields can be achieved using Collectors.groupingBy with a composite key

• Use Collectors.groupingBy with a composite key to group by multiple fields

• Create a class to represent the composite key if necessary

• Example: Map>> groupedData = dataList.stream().collect(Collectors.groupingBy(obj -> obj.getField1() + obj.getField2()))

A project to maintain shopping list

• Create a class or data structure to store items in the shopping list

• Implement functions to add, remove, and update items in the list

• Include functionality to mark items as purchased

• Allow users to view the entire list or filter by category

• Consider adding a feature to set reminders for shopping trips

Use Observer design pattern to track count of hashmap inserts

• Implement an Observer interface with update method to track changes in the hashmap

• Create a concrete observer class to keep track of the count of inserts

• Register the observer with the hashmap to receive notifications on inserts

Static constructor can be overloaded in C#.

• Static constructor is used to initialize static fields of a class.

• Overloading static constructor is useful when we want to initialize different static fields with different values.

• Static constructor is called only once, before the first instance of the class is created.

• Static constructor has no access modifier and no parameters.

Stream is sequential processing while parallel stream allows for concurrent processing in Java.

• Stream is processed sequentially while parallel stream is processed concurrently.

• Parallel stream can improve performance for large datasets by utilizing multiple threads.

• Use parallel stream when order of processing is not important.

• Example: List list = Arrays.asList("a", "b", "c"); list.stream().forEach(System.out::println);

• Example: List list = Arrays.asList("a", "b", "c"); list.par...read more

Thread is a lightweight process that runs concurrently with other threads in a process. A task is a unit of work that can be executed asynchronously.

• Threads are managed by the operating system, while tasks are managed by a task scheduler.

• Threads are more low-level and require more manual management, while tasks are higher-level and can be managed more easily.

• Threads are typically used for parallelism, while tasks are used for asynchronous programming.

• Examples of threading lib...read more

Dependency injection is a design pattern where components are given their dependencies rather than creating them internally.

• Dependency injection helps in achieving loose coupling between classes.

• It allows for easier testing by providing a way to mock dependencies.

• There are three types of dependency injection - constructor injection, setter injection, and interface injection.

Call, apply, and bind are methods in JavaScript used to set the context of a function and pass arguments.

• Call - invokes a function with a specified 'this' value and arguments provided individually.

• Apply - invokes a function with a specified 'this' value and arguments provided as an array.

• Bind - creates a new function that, when called, has its 'this' keyword set to the provided value.

Java8 introduced several new features including lambda expressions, functional interfaces, streams, and default methods.

• Lambda expressions allow for more concise code by enabling functional programming.

• Functional interfaces are interfaces with a single abstract method, which can be implemented using lambda expressions.

• Streams provide a way to work with collections of objects in a functional style, allowing for parallel processing and lazy evaluation.

• Default methods allow inte...read more

The n+1 problem in Hibernate occurs when a query results in multiple individual queries being executed for each row fetched.

• Occurs when a query fetches a collection and then for each element in the collection, another query is executed to fetch related data

• Can be resolved by using fetch joins or batch fetching to reduce the number of queries

• Improves performance by reducing the number of database round trips

Immutable class is a class whose state cannot be modified after creation.

• Make all fields private and final

• Do not provide setter methods

• Ensure deep copy of mutable objects in constructor and getter methods

Core Java is a fundamental programming language used for developing software applications. DSA algorithms are essential for efficient problem-solving.

• Core Java is used for developing software applications and is based on the Java programming language.

• DSA algorithms are data structures and algorithms used for efficient problem-solving.

• Examples of DSA algorithms include sorting algorithms like Bubble Sort and searching algorithms like Binary Search.

DSA problems involve solving algorithmic challenges, while system design involves designing scalable and efficient software systems.

• Practice solving DSA problems on platforms like LeetCode, HackerRank, or CodeSignal.

• Study common data structures and algorithms like arrays, linked lists, trees, sorting algorithms, and searching algorithms.

• For system design, focus on scalability, reliability, performance, and maintainability of software systems.

• Learn about designing distributed ...read more

Internal implementation of hashmap involves an array of linked lists to handle collisions.

• HashMap internally uses an array of linked lists to store key-value pairs.

• When a key is inserted, its hash code is used to determine the index in the array where it should be stored.

• If two keys have the same hash code, they are stored in the same linked list to handle collisions.

• HashMap uses the key's hash code and equals method to find and retrieve values efficiently.