400+ Software Development Engineer Interview Questions and Answers

Use a hashmap to separate prime and non-prime numbers in an array of strings.

• Iterate through the array and convert each string to an integer.

• Use a hashmap to store prime and non-prime numbers based on their divisibility.

• Convert the hashmap back to separate arrays for prime and non-prime numbers.

Efficient way to search a given element in an array of integers with adjacent elements 1+ or 1- from each other.

• Use binary search algorithm to search the element in O(log n) time complexity.

• Check the middle element and compare it with the given element.

• If the middle element is greater than the given element, search in the left half of the array.

• If the middle element is smaller than the given element, search in the right half of the array.

• Repeat until the element is found or t...read more

Measure the height of a room using a thread.

• Tie one end of the thread to a known height point, such as a door handle.

• Hold the other end of the thread and let it hang down to the floor.

• Mark the point where the thread touches the floor.

• Repeat the process at different points in the room to get multiple measurements.

• Take the average of the measurements to estimate the height of the room.

Polymorphism allows objects of different classes to be treated as objects of a common superclass. Interface is a contract that defines a set of methods that a class must implement.

• Polymorphism allows for flexibility in programming by enabling a single interface to be used to represent multiple types of objects

• Interfaces in Java are similar to abstract classes, but they cannot contain any implementation code

• Abstract classes can have both abstract and concrete methods, while in...read more

The program checks if a given sentence is a palindrome or not.

• Prompt the user to input a sentence

• Remove all spaces and punctuation from the sentence

• Reverse the sentence and compare it with the original sentence to check for palindrome

Flattening a nested array involves recursively extracting elements into a single array.

• Use recursion: Define a function that checks if an element is an array. If it is, call the function on that element.

• Example: For input [[1, 2], [3, [4, 5]]], the output should be [1, 2, 3, 4, 5].

• Use Array.prototype.flat(): In JavaScript, you can use the flat method to flatten arrays to a specified depth.

• Example: [1, [2, [3, 4]]].flat(2) results in [1, 2, 3, 4].

• Use reduce: Combine elements i...read more

Prioritize tasks based on deadlines, importance, and impact on overall project goals.

• Evaluate deadlines and prioritize tasks based on urgency

• Consider the importance of each task in relation to project goals

• Assess the impact of completing each task on overall project progress

• Communicate with stakeholders to understand priorities and expectations

• Break down tasks into smaller sub-tasks to manage workload effectively

Stored procedures are used to perform a set of actions, while functions return a single value.

• Stored procedures are precompiled and stored in a database, while functions are compiled at runtime.

• Functions can be used in SQL statements, while stored procedures cannot be used in SQL statements.

• Stored procedures can have input and output parameters, while functions can only have input parameters.

• Functions can be called from within stored procedures, but stored procedures cannot b...read more

DBMS is a software 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 specific model to manage data.

• RDBMS uses tables to store data and relationships between tables are defined by keys.

• Examples of RDBMS include MySQL, Oracle, and SQL Server while examples of DBMS include MongoDB and Cassandr...read more

Find the top k frequent sentences from an array using HashMap and PriorityQueue.

• Use a HashMap to count the frequency of each sentence. For example, for input ['hello', 'world', 'hello'], the map will be {'hello': 2, 'world': 1}.

• Utilize a PriorityQueue (min-heap) to keep track of the top k sentences based on their frequency. If the size exceeds k, remove the least frequent.

• Sort the sentences in the PriorityQueue by frequency and then lexicographically if frequencies are the sa...read more

A news app like InShorts using Flutter & Open News API

• Use Flutter to build the UI for the app

• Integrate Open News API to fetch news articles

• Display news articles in a concise and easy-to-read format

• Allow users to customize their news feed based on topics and sources

• Implement push notifications for breaking news

• Include social sharing options for articles

A photo viewer app for Android devices.

• Use RecyclerView to display a grid of photos

• Implement a caching mechanism to improve performance

• Support gestures for zooming and swiping between photos

• Integrate with a cloud storage service for photo storage and retrieval

• Implement a search feature to allow users to find specific photos

Search for a string in a 2D character matrix in any direction

• Iterate through each cell of the matrix

• For each cell, check all possible directions for the string

• If found, return the starting and ending coordinates of the string

Firebase Dynamic Links is a deep linking platform that allows users to share content across different devices and platforms.

• Firebase Dynamic Links are URLs that allow users to share content across different devices and platforms

• They can be used to redirect users to specific content within an app or website

• They can also be used to track user engagement and measure the effectiveness of marketing campaigns

This function reverses the characters in a given string and returns the reversed string.

• Use Python slicing: `reversed_string = original_string[::-1]`.

• Iterate through the string in reverse: `for char in original_string[::-1]:`.

• Use the `reversed()` function: `''.join(reversed(original_string))`.

• Example: Input: 'hello', Output: 'olleh'.

• Example: Input: '12345', Output: '54321'.

DFS and BFS are graph traversal algorithms. DFS explores as far as possible before backtracking. BFS explores level by level.

• DFS stands for Depth First Search, while BFS stands for Breadth First Search.

• DFS explores as far as possible along each branch before backtracking, while BFS explores level by level.

• DFS uses a stack data structure, while BFS uses a queue data structure.

• DFS is often used for solving problems like finding connected components, topological sorting, and sol...read more

SQL basics include DDL for defining database structures and DML for manipulating data within those structures.

• DDL (Data Definition Language) includes commands like CREATE, ALTER, and DROP to define and modify database structures.

• Example of DDL: CREATE TABLE users (id INT PRIMARY KEY, name VARCHAR(100));

• DML (Data Manipulation Language) includes commands like SELECT, INSERT, UPDATE, and DELETE to manage data within tables.

• Example of DML: INSERT INTO users (id, name) VALUES (1, ...read more

Design a parking lot system to manage parking spaces, vehicles, and payment processing efficiently.

• Define classes: ParkingLot, ParkingSpace, Vehicle, Ticket, Payment.

• ParkingLot can have multiple ParkingSpaces categorized by type (e.g., compact, standard, oversized).

• Implement methods for parking a vehicle, retrieving a vehicle, and processing payments.

• Use a hashmap to track parked vehicles and their corresponding tickets for quick access.

• Consider edge cases like full parking l...read more

The number of binary strings of length N without consecutive 1s.

• Use dynamic programming to solve the problem.

• Create an array to store the number of valid strings for each length.

• Initialize the array with base cases.

• Iterate through the array and calculate the number of valid strings for each length.

• Return the value at the Nth index of the array.

I follow a systematic approach to debug JavaScript code.

• Identify the problem area and reproduce the issue

• Use console.log() to print values and debug

• Use browser developer tools to step through code

• Check for syntax errors and typos

• Use a linter to catch common errors

• Use a debugger tool like Chrome DevTools

• Break down the code into smaller parts for easier debugging

Solve a puzzle by writing a C program to manipulate strings or arrays effectively.

• Use arrays of strings to store multiple strings, e.g., char *arr[] = {'apple', 'banana', 'cherry'};

• Implement string manipulation functions like strlen, strcpy, and strcat for handling strings.

• Consider edge cases such as empty strings or maximum length strings when designing your solution.

• Utilize loops to iterate through arrays and perform operations on each string.

Check if an array of strings is sorted in ascending or descending order.

• Iterate through the array and compare adjacent elements.

• For ascending order, check if each element is less than or equal to the next.

• For descending order, check if each element is greater than or equal to the next.

• Example: ['apple', 'banana', 'cherry'] is ascending; ['cherry', 'banana', 'apple'] is descending.

Protected access modifier restricts interface method access to only derived or implemented classes.

• Use 'protected' access modifier to restrict access to only derived or implemented classes

• Protected members are accessible within the same package or by subclasses

• Example: 'protected void methodName() {}' in an interface

Binary search has O(log n) time complexity for arrays and O(n) for linked lists.

• Binary search is efficient for arrays due to their random access nature.

• Linked lists require sequential traversal, making binary search inefficient.

• For arrays, the time complexity is O(log n) as the search space is halved with each iteration.

• For linked lists, the time complexity is O(n) as all nodes must be visited to find the target.

• Binary search can be implemented recursively or iteratively.

Use a sliding window approach to search for a substring in a larger string without using built-in functions.

• Iterate through the larger string using a window of the size of the substring to search for.

• Compare the characters in the window with the substring to check for a match.

• Move the window one character at a time until the end of the larger string is reached.

• Time complexity is O(n*m) where n is the length of the larger string and m is the length of the substring.

An update query in SQL is used to modify existing records in a database table.

• Use the UPDATE keyword followed by the table name

• Set the column(s) to be updated using SET keyword

• Specify the new values for the column(s)

• Add a WHERE clause to specify which records to update

SQL is best for structured data, NoSQL for unstructured. Use SQL for complex queries, NoSQL for scalability and speed.

• SQL is best for structured data, NoSQL for unstructured

• Use SQL for complex queries, NoSQL for scalability and speed

• SQL is ACID compliant, NoSQL is BASE

• Examples of SQL: MySQL, Oracle, PostgreSQL

• Examples of NoSQL: MongoDB, Cassandra, Redis