20+ DE Shaw Software Developer Interview Questions and Answers for Freshers

The task is to determine the minimum number of towers needed to stack cubes in a specific order.

• Iterate through the array of cubes and maintain a stack to keep track of towers.

• For each cube, check if it can be placed on an existing tower or start a new one.

• Update the stack based on the cube's size and count the number of towers needed.

• Return the minimum number of towers required.

• Example: For input N = 3, ARR = [3, 2, 1], the output should be 1.

Calculate uneaten carrots by rabbits with specific jumping factors.

• Iterate through each carrot and check if any rabbit jumps on it.

• Use the jumping factors to determine which carrots will be eaten.

• Subtract the eaten carrots from the total to get the uneaten carrots.

Given an array of coin values, determine the maximum value Wong can obtain by playing a coin game against Dr. Strange.

• Wong plays first and can remove one coin from either end of the array on each turn.

• The game ends when no coins are left, and the player with the highest total value wins.

• Consider different scenarios like having an odd or even number of coins in the array.

Calculate the total money accumulated by Harshit in Ninja bank after N days with a specific increment strategy.

• Start with 1 rupee on the first Monday and increase by 1 rupee each day from Tuesday to Sunday.

• Each new Monday starts with an additional rupee more than the previous Monday's deposit.

• Calculate the total amount of money accumulated after N days for each test case.

• Example: For N = 2, total amount is 3 rupees; for N = 5, total amount is 15 rupees.

Identify K most frequent elements in an array and return them sorted in ascending order.

• Use a hashmap to store the frequency of each element in the array.

• Sort the elements based on their frequency in descending order.

• Return the first K elements from the sorted list.

Find the maximum profit that can be obtained by completing at most two transactions of buying and selling a stock.

• Iterate through the array of stock prices and calculate the maximum profit that can be obtained by completing at most two transactions.

• Keep track of the maximum profit that can be obtained by selling the stock on each day after buying it on a previous day.

• Consider all possible combinations of two transactions to find the maximum profit.

• Return the maximum profit fo...read more

The problem involves finding the minimum number of elements to remove from an array so that the difference between the maximum and minimum element is less than or equal to a given value.

• Iterate through the array and keep track of the minimum and maximum elements.

• Calculate the difference between the maximum and minimum elements.

• If the difference is greater than the given value, increment the count of elements to remove.

• Return the count of elements to remove as the result.

Given a tree structure of kingdoms, determine if it's possible to conquer more kingdoms than Aragorn by strategically choosing the starting kingdom.

• Start at the kingdom adjacent to Aragorn's initial kingdom

• Choose the kingdom that allows you to capture the most number of kingdoms in subsequent turns

• Consider the tree structure to plan your conquest strategically

Find the minimum number of taps needed to water the entire garden using given tap ranges.

• Iterate over taps and update the farthest point each tap can reach.

• Use a greedy approach to select the tap that can water the farthest point.

• If a tap can't water any point, return -1.

• Example: For ranges = [3, 4, 1, 1, 0, 0], tap at position 1 can water the entire garden.

The task is to determine the maximum profit that can be achieved by performing up to two buy-and-sell transactions on a given set of stock prices.

• Iterate through the array of stock prices and calculate the maximum profit that can be achieved by buying and selling at different points.

• Keep track of the maximum profit after the first transaction and the maximum profit after the second transaction.

• Return the sum of these two maximum profits as the final result.

• Example: For input ...read more

Find the magic index in a sorted array where A[i] = i.

• Use binary search to efficiently find the magic index in the sorted array.

• Check the middle element of the array and compare it with its index to determine the direction to search.

• Repeat the process on the left or right half of the array until the magic index is found or no more elements to search.

Default constructor is provided by the compiler if no constructor is defined. Copy constructor creates a new object by copying an existing object.

• Default constructor initializes member variables to default values.

• Copy constructor creates a new object with the same values as an existing object.

• Default constructor is called automatically by the compiler if no constructor is defined.

• Copy constructor is called when an object is passed by value or when a new object is initialized ...read more

Primary key uniquely identifies a record in a table, while unique key ensures that all values in a column are distinct.

• Primary key can't have null values, while unique key can have one null value.

• A table can have only one primary key, but multiple unique keys.

• Primary key is used as a foreign key in other tables, while unique key is not.

• Example: Primary key - employee ID, Unique key - email address.

Truncate removes all data from a table while Delete removes specific data from a table.

• Truncate is faster than Delete as it doesn't log individual row deletions.

• Truncate resets the identity of the table while Delete doesn't.

• Truncate can't be rolled back while Delete can be.

• Truncate doesn't fire triggers while Delete does.

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.

DML is Data Manipulation Language used to manipulate data in a database. DLL is Data Definition Language used to define database schema.

• DML is used to insert, update, delete data in a database.

• DLL is used to create, alter, drop database objects like tables, views, indexes.

• DML statements include INSERT, UPDATE, DELETE.

• DLL statements include CREATE, ALTER, DROP.

• DML affects data in a database, DLL affects the structure of a database.

DBMS is a software system to manage databases while RDBMS is a type of DBMS that uses a relational model.

• DBMS stands for Database Management System while RDBMS stands for Relational Database Management System.

• DBMS can manage any type of database while RDBMS uses a relational model to manage data.

• DBMS does not enforce any specific data model while RDBMS enforces a relational data model.

• Examples of DBMS include MongoDB, Cassandra, and Redis while examples of RDBMS include MySQL...read more

Normalisation is the process of organizing data in a database to reduce redundancy and improve data integrity.

• Normalisation helps to eliminate data redundancy and inconsistencies

• It ensures that each piece of data is stored in only one place

• It helps to improve data integrity and accuracy

• It makes it easier to maintain and update the database

• There are different levels of normalisation, each with its own set of rules and guidelines

Class access modifiers are keywords used to control the visibility and accessibility of class members.

• There are four access modifiers in Java: public, private, protected, and default

• Public members can be accessed from anywhere

• Private members can only be accessed within the same class

• Protected members can be accessed within the same class, subclasses, and same package

• Default members can be accessed within the same package

Access specifiers are keywords in object-oriented programming languages that determine the visibility and accessibility of class members.

• Access specifiers are used to restrict access to class members.

• There are three types of access specifiers: public, private, and protected.

• Public members can be accessed from anywhere in the program.

• Private members can only be accessed within the class.

• Protected members can be accessed within the class and its subclasses.

• Example: class MyClas...read more

Library functions are pre-written code that can be reused to perform common tasks.

• Library functions save time and effort by providing pre-written code.

• They are often included in programming languages or external libraries.

• Examples include functions for string manipulation, mathematical calculations, and file input/output.

• Library functions can be called from within a program to perform specific tasks.

• They can also be customized or extended to fit specific needs.

Recursion function is a function that calls itself until a base condition is met.

• Recursion is a technique used to solve problems by breaking them down into smaller sub-problems.

• It involves a function calling itself with a modified input until a base case is reached.

• Recursion can be used to solve problems such as factorial, Fibonacci series, and binary search.

• Recursion can be implemented using loops as well, but it may not always be efficient.

• Recursion can lead to stack overfl...read more

Serialization is the process of converting an object into a format that can be stored or transmitted.

• Serialization is used to save the state of an object and recreate it later.

• It is commonly used in network communication to transmit data between different systems.

• Examples of serialization formats include JSON, XML, and binary formats like Protocol Buffers.

• Deserialization is the opposite process of converting serialized data back into an object.

Inheritance is a mechanism in object-oriented programming where a new class is created by inheriting properties of an existing class.

• Inheritance allows code reusability and saves time and effort in programming.

• The existing class is called the superclass or parent class, and the new class is called the subclass or child class.

• The subclass inherits all the properties and methods of the superclass and can also add its own unique properties and methods.

• For example, a class 'Anima...read more

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

• Elements are added to the top of the stack and removed from the top.

• Common operations include push (add element) and pop (remove element).

• Stacks can be implemented using arrays or linked lists.

• Examples include the call stack in programming and the undo/redo feature in text editors.

Assembly is a low-level programming language that is used to write programs that can directly interact with computer hardware.

• Assembly language is specific to a particular computer architecture.

• It is a low-level language that is difficult to read and write.

• Assembly language programs are faster and more efficient than programs written in high-level languages.

• Examples of assembly language include x86, ARM, and MIPS.

• Assembly language is often used for system-level programming, d...read more

Answering OOP Java design problems

• Identify the problem domain and create a class hierarchy

• Use encapsulation to hide implementation details

• Apply inheritance to reuse code and create subtypes

• Implement polymorphism to allow objects to take on multiple forms

• Avoid tight coupling and favor composition over inheritance

• Use design patterns to solve common problems

• Consider SOLID principles for maintainable code