100+ Software Engineer Intern Interview Questions and Answers

Check if two binary trees are mirrors of each other based on specific criteria.

• Compare the roots of both trees.

• Check if the left subtree of the first tree is the mirror of the right subtree of the second tree.

• Verify if the right subtree of the first tree is the mirror of the left subtree of the second tree.

Partition array into two subsets to minimize absolute difference in sum.

• Sort the array in non-decreasing order.

• Calculate the total sum of all elements in the array.

• Iterate through the array and find the subset sum closest to half of the total sum.

• The minimum absolute difference will be the absolute difference between total sum and twice the subset sum.

The task is to modify a given matrix such that if any element in a row or column is 0, then make all elements in that row and column 0.

• Iterate through the matrix and keep track of rows and columns that contain 0s

• After the first iteration, iterate through the tracked rows and columns and set all elements to 0

• Handle the case where the first row or column contains 0 separately

• To solve with O(1) space complexity, use the first row and first column of the matrix to track the rows ...read more

The problem is to connect N ropes of different lengths into one rope with minimum cost.

• Sort the array of rope lengths in ascending order.

• Initialize a variable to keep track of the total cost.

• While there are more than one rope remaining, take the two shortest ropes and connect them.

• Add the cost of connecting the two ropes to the total cost.

• Replace the two shortest ropes with the connected rope.

• Repeat the above steps until only one rope remains.

• Return the total cost.

The task is to determine if two strings are similar based on the given conditions.

• Check if the strings are equal, if yes, return 1

• Divide both strings into two parts and check if any combination satisfies the similarity condition

• If none of the conditions hold true, return 0

Implement Merge Sort algorithm to sort a sequence of numbers in non-descending order.

• Divide the input array into two halves recursively until each array has only one element.

• Merge the sorted halves to produce a completely sorted array.

• Time complexity of Merge Sort is O(n log n).

Given a linked list of coordinates, find the starting nodes of segments with maximum and minimum slopes between consecutive points.

• Traverse the linked list and calculate slopes between consecutive points

• Identify the segments with maximum and minimum slopes

• Return the starting nodes of these segments

Check if the binary representation of a given integer is a palindrome.

• Convert the integer to binary representation

• Check if the binary representation is a palindrome by comparing it with its reverse

• Return true if it is a palindrome, false otherwise

The maximum sum from root to leaf in a binary tree, where only parent or child can be included in the sum.

• Use a recursive approach to traverse the binary tree.

• At each node, calculate the maximum sum from its left and right child.

• Compare the sums and return the maximum sum plus the value of the current node.

• Repeat this process until reaching a leaf node.

• Track the maximum sum encountered during the traversal.

Software Development Cycle is a process of designing, creating, testing, and deploying software.

• The phases of Software Development Cycle are Planning, Analysis, Design, Implementation, Testing, Deployment, and Maintenance.

• Planning involves defining the project scope, goals, and requirements.

• Analysis involves gathering and analyzing user requirements.

• Design involves creating a detailed design of the software.

• Implementation involves writing code and integrating different compon...read more

Architecting a storage solution involves scalability, reliability, and performance optimization to meet industry demands.

• Identify key requirements: Understand the specific needs of the storage industry, such as data volume, access speed, and security.

• Choose the right architecture: Consider distributed systems for scalability, like using cloud storage solutions (e.g., AWS S3).

• Implement redundancy: Use techniques like RAID or replication to ensure data durability and availabili...read more

Determine which finger corresponds to a number using a simple mapping technique for constant time retrieval.

• Use an array to represent fingers: fingers = ['Thumb', 'Index', 'Middle', 'Ring', 'Pinky']

• Access the finger by index: for number 1, return fingers[0] (Thumb), for 2, return fingers[1] (Index).

• This approach ensures O(1) time complexity since array access is constant time.

Design a rate limiter allowing 5 API calls per minute, with variations for premium users.

• Use a sliding window algorithm to track API calls within the last minute.

• Store user call counts in a hash map with timestamps.

• For premium users, allow a higher limit, e.g., 10 calls per minute.

• Return false if the limit is exceeded, otherwise return true.

• Consider edge cases like simultaneous requests at the limit.

Waterfall model is a linear sequential approach to software development.

• Phases: Requirements gathering, Design, Implementation, Testing, Deployment, Maintenance

• Each phase must be completed before moving to the next

• No going back to previous phases

• Documentation is important

• Less flexible than Agile model

Design a store management system with relevant schema tables

• Create a 'Store' table with attributes like store_id, name, location, etc.

• Design a 'Product' table with attributes like product_id, name, price, quantity, etc.

• Include a 'Sales' table to track sales transactions with attributes like sale_id, date, total_amount, etc.

• Implement a 'Stock' table to manage product stock levels with attributes like stock_id, product_id, quantity_available, etc.

Psuedo code output and technical MCQs for Software Engineer Intern position

• Provide examples for technical MCQs

• Psuedo code output needs to be calculated

• Assess candidate's technical knowledge

Program to print all Prime Numbers up to the input number using Prime Sieve Algorithm.

• Create a boolean array of size n+1 and initialize all values as true.

• Loop through the array starting from 2 and mark all multiples of each prime number as false.

• Print all the numbers that are still marked as true in the array.

I would rate myself a 7/10 in C++, with solid understanding and practical experience in various projects.

• Strong grasp of C++ fundamentals, including OOP concepts like inheritance and polymorphism.

• Experience with STL (Standard Template Library) for efficient data handling, e.g., using vectors and maps.

• Worked on a project involving multithreading, improving performance by implementing thread-safe data structures.

• Familiar with memory management in C++, including pointers and dyn...read more

Query to find the nth highest salary from a database

• Use ORDER BY and LIMIT in the query

• Consider handling ties if multiple employees have the same salary

• Example: SELECT DISTINCT salary FROM employees ORDER BY salary DESC LIMIT n-1, 1

Minimum weight to reach bottom right corner in matrix starting from top left. You can move only down and right.

• Use dynamic programming to solve the problem efficiently

• Create a 2D array to store the minimum weight to reach each cell

• The minimum weight to reach a cell is the minimum of the weight to reach the cell above and the cell to the left plus the weight of the current cell

• The minimum weight to reach the bottom right corner is the value in the last cell of the 2D array

The 4 pillars of object oriented programming are encapsulation, inheritance, polymorphism, and abstraction.

• Encapsulation: Bundling data and methods that operate on the data into a single unit.

• Inheritance: Creating new classes based on existing classes, allowing for code reuse.

• Polymorphism: The ability for objects of different classes to respond to the same message.

• Abstraction: Hiding the complex implementation details and only showing the necessary features.

Access modifiers in Java control the visibility and accessibility of classes, methods, and variables.

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

• Public: accessible from any other class.

• Private: accessible only within the same class.

• Protected: accessible within the same package and subclasses.

• Default: accessible only within the same package.

• Example: public class MyClass { private int myVar; protected void myMethod() {}}

Debugging a Tic Tac Toe game in React involves fixing state management and rendering issues.

• Check state initialization: Ensure the game state is initialized correctly, e.g., `const [squares, setSquares] = useState(Array(9).fill(null));`.

• Verify event handlers: Ensure the click handlers update the state properly, e.g., `handleClick(i) { const newSquares = squares.slice(); newSquares[i] = xIsNext ? 'X' : 'O'; setSquares(newSquares); }`.

• Ensure rendering logic is correct: Check if...read more

Implement a binary search in each row of a sorted 2D matrix to achieve O(mlogn) time complexity.

• Divide and conquer approach can be used to search in each row of the matrix.

• Perform binary search on each row to find the target element efficiently.

• Ensure the rows are sorted to apply binary search in each row.

Find the nearest index of a character in a string for each index.

• Create an array of strings to store the results.

• Loop through each character in the string.

• For each character, loop through the rest of the string to find the nearest index of the same character.

• Store the result in the array.

OOP concepts are fundamental principles in object-oriented programming that help in organizing and designing code.

• Encapsulation: Bundling data and methods that operate on the data into a single unit (class).

• Inheritance: Allowing a class to inherit properties and behavior from another class.

• Polymorphism: The ability for objects of different classes to respond to the same message in different ways.

• Abstraction: Hiding the complex implementation details and showing only the neces...read more

Design a category schema with multiple subcategories

• Use a parent-child relationship to link categories and subcategories

• Implement a tree data structure to represent the hierarchy

• Each category can have multiple subcategories

• Example: Category - Electronics, Subcategories - Computers, Mobile Phones, TVs