80+ Software Development Engineer Interview Questions and Answers for Freshers

The question asks to find the similarity between two words by normalizing the length of the longest common subsequence (LCS) by the total length of the string.

• Implement a function that takes two words as input

• Find the length of the longest common subsequence (LCS) between the two words

• Normalize the length of LCS by dividing it by the total length of the string

• Return the normalized similarity value

To find least common ancestor of two nodes in a binary tree, traverse the tree from root to the nodes and store the paths. Then compare the paths to find the common ancestor.

• Traverse the binary tree from root to the two nodes and store the paths

• Compare the paths to find the common ancestor

• If the binary tree is a BST, compare the values of the nodes to find the common ancestor

• If one of the nodes is the ancestor of the other, return the ancestor node

Implement Facebook's 'People you may know' feature using BFS and mutual friend counter.

• Create a graph of users and their friends

• Perform BFS on the graph starting from the user in question

• For each friend of the user, increment a counter for their mutual friends

• Sort the list of potential friends by mutual friend count

• Exclude already connected friends and suggest top potential friends

To identify swapped nodes in a binary search tree, we need to perform an inorder traversal and compare adjacent nodes.

• Perform an inorder traversal of the binary search tree

• Compare each node with its adjacent node

• If a node is smaller than its previous node, mark it as a swapped node

• If two nodes are swapped, swap their values to restore the original binary search tree

Find the heavier ball from 8 identical balls using a balance weighting machine in least number of tries.

• Divide the balls into 3 groups of 3, 3, and 2 balls.

• Weigh the first two groups against each other.

• If they balance, the heavier ball is in the remaining group of 2 balls.

• If one group is heavier, weigh two balls from that group against each other.

• If they balance, the heavier ball is the remaining ball.

• If one ball is heavier, that is the heavier ball.

Design ADT for chess game classes

• Create classes for pieces (king, queen, etc.), board, player, game

• Use inheritance to represent different types of pieces

• Implement methods for moving pieces, checking for checkmate, etc.

Optimizing for binary search tree

• Ensure the tree is balanced to maintain O(log n) search time

• Implement efficient insertion and deletion algorithms

• Use in-order traversal for sorted output

• Consider using AVL or Red-Black trees for self-balancing

• Avoid using recursion for large trees to prevent stack overflow

Code for subtitle syncing application

• Create a function to parse subtitle file and extract time stamps

• Create a function to parse video file and extract time stamps

• Calculate time difference between subtitle and video time stamps

• Adjust subtitle time stamps accordingly

• Output synced subtitle file

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

Bean annotation is used in Spring Boot on class or method to indicate that a method produces a bean to be managed by the Spring container.

• Bean annotation is used on methods within a class to indicate that the method produces a bean to be managed by the Spring container.

• It can also be used at the class level to indicate that the class itself is a Spring bean.

• For example, @Bean annotation can be used on a method that creates and returns a DataSource bean in a configuration clas...read more

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

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

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'.

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

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.

AI logic for Chess representation

• Implement minimax algorithm with alpha-beta pruning

• Use evaluation function to assign values to board positions

• Implement move ordering to improve efficiency

• Use transposition tables to store previously evaluated positions

• Implement iterative deepening to improve search depth

Static keyword is used to create class-level variables and methods, while final keyword is used to make a variable constant.

• Static keyword is used to create variables and methods that belong to the class itself, rather than to any specific instance of the class.

• Final keyword is used to make a variable constant and cannot be changed once it has been assigned a value.

• Static variables are shared among all instances of a class, while final variables are unique to each instance.

Choosing the right technology involves assessing project requirements, team expertise, and long-term maintainability.

• Evaluate project requirements: Understand the specific needs, such as performance, scalability, and security.

• Consider team expertise: Leverage technologies that your team is already familiar with to reduce the learning curve.

• Assess community support: Choose frameworks with strong community backing for better resources and troubleshooting.

• Look at long-term maint...read more

Initiating a software project involves defining goals, gathering requirements, and planning resources effectively.

• Define project goals and objectives clearly. For example, 'Develop a mobile app for online shopping.'

• Conduct a feasibility study to assess technical and financial viability.

• Gather and document requirements from stakeholders, such as user stories or use cases.

• Assemble a project team with the necessary skills, like developers, designers, and testers.

• Create a project...read more

Answering questions on finding palindromes and remainders without modulus operator.

• To find a palindrome, compare the first and last characters of the string and move towards the center until they meet or the string is not a palindrome.

• To find the longest palindrome, iterate through all possible substrings and check if they are palindromes.

• To find remainder without modulus operator, use repeated subtraction until the dividend is less than the divisor.

Microservices interact with each other through APIs, messaging, or events.

• Microservices communicate with each other through APIs, which can be synchronous or asynchronous.

• Messaging systems like RabbitMQ or Kafka can be used for communication between microservices.

• Events can be used for loosely coupled communication between microservices.

• Service discovery mechanisms like Eureka or Consul help microservices locate and communicate with each other.

• API gateways can be used to mana...read more

A palindrome is a string that reads the same forwards and backwards. Check by comparing characters from both ends.

• 1. Initialize two pointers: one at the start and one at the end of the string.

• 2. Compare the characters at both pointers. If they are not the same, it's not a palindrome.

• 3. Move the left pointer right and the right pointer left, and repeat the comparison.

• 4. If all characters match, the string is a palindrome.

• Example: 'racecar' is a palindrome, while 'hello' is not...read more

SQL commands like SELECT, INSERT, GRANT, and REVOKE manage data retrieval, insertion, and user permissions in databases.

• SELECT: Retrieves data from one or more tables. Example: SELECT * FROM users;

• INSERT: Adds new records to a table. Example: INSERT INTO users (name, age) VALUES ('Alice', 30);

• GRANT: Provides specific privileges to users. Example: GRANT SELECT ON users TO user1;

• REVOKE: Removes specific privileges from users. Example: REVOKE SELECT ON users FROM user1;

Swap 2 numbers without using 3rd variable

• Use addition and subtraction

• Use multiplication and division

• Use bitwise XOR operation

Find the next greatest number for each integer in an array in O(N) time complexity.

• Iterate through the array from right to left

• Use a stack to keep track of potential next greatest numbers

• Pop elements from the stack that are less than the current element and update their next greatest number to the current element

• Push the current element onto the stack

• Repeat until all elements have a next greatest number