80+ Software Engineer Level 1 Interview Questions and Answers

The program reads a file and selects the first 3 lines. It then identifies the longest line and counts the number of words in that line.

• Read the file using appropriate file handling methods

• Store the first 3 lines in an array of strings

• Iterate through the array to find the longest line

• Count the number of words in the longest line using string manipulation methods

O(nk) is better than O(n) for large data and hash tables.

• O(nk) is better because it takes into account the size of the data and the number of keys.

• For large data and hash tables, the size of n will be large, making O(nk) more efficient.

• O(n) assumes a constant number of keys, which may not be the case in practice.

• Amazon may have chosen O(nk) for better scalability and performance.

Amazon displays only a subset of search results based on various factors like relevance, popularity, and user preferences.

• Amazon uses algorithms to determine which products to display in search results.

• Factors considered include product relevance, customer reviews, sales rank, and availability.

• Machine learning techniques may be used to personalize search results based on user behavior and preferences.

• Amazon also considers factors like seller reputation and fulfillment options...read more

The question is about finding the shortest path in a 3x3 matrix with weighted edges.

• This is a graph traversal problem.

• Use a graph algorithm like Dijkstra's algorithm or A* search to find the shortest path.

• Assign weights to the edges and calculate the sum of weights for each possible path.

• Choose the path with the smallest sum of weights as the shortest path.

To check internet connectivity, you can use various methods like pinging a website or checking network status.

• Use the command 'ping www.google.com' to see if you receive a response.

• Check network settings in your operating system for connectivity status.

• Use tools like 'traceroute' to diagnose network paths and issues.

• In programming, use libraries like 'requests' in Python to attempt a web request.

The product will be the key and the brands will be the values.

• The key in this case refers to the unique identifier for each product.

• The values are the different brands associated with each product.

• For example, if the product is a smartphone, the key could be the model number and the values could be the different brands that manufacture that model.

Use a MinHeap to efficiently find the kth largest element in an array.

• 1. Create a MinHeap of size k to store the largest k elements.

• 2. Iterate through the array, adding elements to the MinHeap.

• 3. If the size of the MinHeap exceeds k, remove the smallest element.

• 4. After processing all elements, the root of the MinHeap is the kth largest element.

• Example: For array [3, 2, 1, 5, 6, 4] and k=2, the MinHeap will contain [5, 6] and the root will be 5.

Find the shortest palindrome in an array of strings using O(n^2) time complexity.

• A palindrome reads the same forwards and backwards, e.g., 'racecar'.

• Iterate through each string in the array and check if it's a palindrome.

• Keep track of the shortest palindrome found during the iteration.

• Example: For ['abc', 'a', 'aba', 'xyz'], the shortest palindrome is 'a'.

• Use two pointers to check for palindrome properties efficiently.

Typing www.google.com initiates a series of network requests to load the webpage in your browser.

• 1. DNS Resolution: The browser queries a DNS server to translate www.google.com into an IP address.

• 2. TCP Connection: A TCP connection is established with the server using the IP address.

• 3. HTTP Request: The browser sends an HTTP request to the server for the webpage.

• 4. Server Response: The server processes the request and sends back the HTML content of the page.

• 5. Rendering: The ...read more

Hash tables are a data structure that uses a hash function to map keys to values, providing efficient lookup, insertion, and deletion.

• Hash tables use a hash function to convert keys into array indices.

• They provide constant-time average case complexity for search, insert, and delete operations.

• Collisions can occur when different keys map to the same index, which can be resolved using techniques like chaining or open addressing.

• Examples of hash table implementations include Pyt...read more

Intersection of two linked lists is finding the common node(s) between them.

• Traverse both lists simultaneously and compare each node to find the intersection point.

• Use a hash set to store nodes of one list and check for intersection in the other list.

• Optimize by finding the lengths of both lists and aligning the pointers before comparison.

React is a JavaScript library for building user interfaces. NPM is a package manager for JavaScript.

• React is used for creating interactive UI components

• NPM is used for managing dependencies and packages in JavaScript projects

• I used React in my project for its component-based architecture and virtual DOM efficiency

• I used NPM in my project to easily install and manage third-party libraries and tools

Creating a Spring Boot backend service from scratch involves setting up database connection, creating entities, repositories, services, controllers, and handling client requests.

• Set up database connection in application.properties file

• Create entity classes representing database tables

• Create repository interfaces extending JpaRepository for database operations

• Create service classes to implement business logic

• Create controller classes to handle client requests and map them to a...read more

Implement a stack with a method to return the minimum number in O(1) time complexity

• Create a stack to store numbers and another stack to store minimum numbers encountered so far

• When pushing a number, check if it is smaller than the current minimum and push it to the minimum stack

• When popping a number, check if it is the current minimum and pop from the minimum stack if necessary

• The top of the minimum stack will always have the current minimum number

Use binary search to find the key in a sorted and rotated array.

• Apply binary search to efficiently find the key in the array.

• Check if the key is in the left or right half of the array based on the mid element.

• Adjust the search space accordingly based on the comparison of key with elements at start, mid, and end of the array.

Merge two arrays, remove duplicates, and sort without using built-in functions.

• Use a set to collect unique elements from both arrays. Example: ['apple', 'banana'], ['banana', 'cherry'] -> {'apple', 'banana', 'cherry'}.

• Convert the set back to an array for sorting. Example: ['apple', 'banana', 'cherry'].

• Implement a sorting algorithm like bubble sort or insertion sort to sort the array manually.

• Return the final sorted array without duplicates.

Radix sort has a running time of O(nk), where n is the number of elements and k is the length of the longest element.

• Radix sort is a non-comparative sorting algorithm that sorts elements by their individual digits or characters.

• It works by distributing the elements into 10 buckets based on the value of the least significant digit, then repeatedly redistributing them based on the next significant digit.

• The process continues until all digits have been considered, resulting in a...read more

Time complexity analysis helps determine the efficiency of algorithms, especially in loops.

• Time complexity is often expressed using Big O notation, e.g., O(n) for linear time.

• A simple loop iterating through an array of size n has a time complexity of O(n).

• Nested loops multiply their complexities, e.g., two nested loops each iterating n times result in O(n^2).

• Constant time operations inside a loop do not affect the overall complexity, e.g., O(n) remains O(n) if you add O(1) op...read more

Find the maximum area rectangle with all boundaries as 1 in a matrix of 0 and 1.

• Use dynamic programming to calculate the maximum area rectangle.

• Iterate through each row of the matrix and calculate the maximum area rectangle with that row as the base.

• Keep track of the maximum area rectangle seen so far.

• Time complexity: O(n^2), where n is the number of rows in the matrix.

Java is statically typed, object-oriented language with a focus on performance and scalability. Python is dynamically typed, high-level language known for its simplicity and readability.

• Java is statically typed, meaning variable types are explicitly declared at compile time. Python is dynamically typed, allowing for more flexibility but potentially leading to runtime errors.

• Java is more verbose and requires more boilerplate code compared to Python, which emphasizes readabilit...read more

Storage class specifiers in C define the scope and lifetime of variables.

• auto - default storage class for local variables

• extern - used to declare a global variable in another file

• static - retains the value of a variable between function calls

• register - suggests to the compiler to store the variable in a register for faster access

Event bubbling is a JavaScript event propagation mechanism where events propagate from child to parent elements.

• Event bubbling allows for event delegation, reducing the number of event listeners needed.

• Example: A click event on a button inside a div can be handled by the div's event listener.

• It helps in managing events for dynamically added elements without needing to reattach listeners.

• Example: If a list item is added to a list, the existing click event on the list can still...read more

Program to check if a string can be rearranged to form a palindrome

• Create a frequency map of characters in the string

• Count the number of characters with odd frequencies

• If there is at most one character with odd frequency, the string can be rearranged to form a palindrome

Merging two dictionaries combines their key-value pairs into a single dictionary.

• Use the `update()` method to merge: dict1.update(dict2).

• Use dictionary unpacking: merged_dict = {**dict1, **dict2}.

• In Python 3.9+, use the merge operator: merged_dict = dict1 | dict2.

• Example: dict1 = {'a': 1}, dict2 = {'b': 2} results in {'a': 1, 'b': 2}.

I have intermediate level experience in programming with Java, Python, and C++.

• I have worked on projects involving data structures and algorithms.

• I have experience with object-oriented programming and design patterns.

• I have developed web applications using frameworks like Spring and Django.

• I have also worked on projects involving machine learning and natural language processing.

• I am comfortable working with databases and have experience with SQL and NoSQL databases.

Using triple join in SQL to combine data from three related tables effectively.

• A triple join combines three tables based on related columns.

• Example: Joining 'employees', 'departments', and 'salaries' tables.

• Use INNER JOIN for matching records across all tables.

• Consider LEFT JOIN if you want to include all records from one table.

Use a subquery to find the 2nd largest number in a database table.

• Use a subquery to select all distinct numbers from the table

• Order the numbers in descending order

• Use LIMIT 1,1 to select the second row which will be the 2nd largest number