100+ SDE (Software Development Engineer) Interview Questions and Answers

Ingress is a Kubernetes resource that manages external access to services. Prometheus is a monitoring system and Grafana is a visualization tool.

• Ingress is used to route external traffic to the appropriate Kubernetes service

• Prometheus is used to collect and store metrics from various sources

• Grafana is used to visualize the collected metrics in a user-friendly way

• Ingress can be configured to use different load balancing algorithms

• Prometheus has a powerful query language for an...read more

To check if a string is palindrome or not.

• Compare the first and last characters of the string and continue towards the middle until all characters have been compared.

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

• If any characters do not match, the string is not a palindrome.

To find length, frequency of each character and list of unique characters of a string.

• Iterate through the string and count the frequency of each character using a hash table.

• Create a list of unique characters by iterating through the hash table.

• Calculate the length of the string using the built-in length function.

• Return the frequency, length and list of unique characters as an array of strings.

The answer is -22

• Perform multiplication first

• Then perform addition and subtraction from left to right

Lexical scoping is a way of defining variable scope based on where they are declared in the code.

• Variables declared inside a function have local scope and are not accessible outside the function.

• Variables declared outside a function have global scope and can be accessed from anywhere in the code.

• Nested functions can access variables declared in their parent function.

• Example: function outer() { let x = 10; function inner() { console.log(x); } inner(); } outer(); // Output: 10

Check if a binary tree is a binary search tree or not.

• Traverse the tree in-order and check if the elements are in sorted order.

• Check if the left child is less than the parent and the right child is greater than the parent.

• Use recursion to check if all the subtrees are BSTs.

• Maintain a range for each node and check if the node value is within that range.

Find the maximum continuous sum in an array of integers.

• Use Kadane's algorithm to find the maximum subarray sum in linear time complexity.

• Initialize two variables, one for current maximum sum and another for overall maximum sum.

• Iterate through the array and update the variables accordingly.

• Example: For array [-2, 1, -3, 4, -1, 2, 1, -5, 4], the maximum continuous sum is 6 (from index 3 to 6).

Yes, high and low level design principles are important in software development.

• High level design principles focus on overall architecture and system organization.

• Low level design principles focus on implementation details and code structure.

• Examples of high level design principles include SOLID, DRY, and KISS.

• Examples of low level design principles include naming conventions, code commenting, and code formatting.

• Both high and low level design principles are important for cre...read more

Sort an array of 0s, 1s, and 2s in O(n) time complexity.

• Use three pointers to keep track of the positions of 0s, 1s, and 2s.

• Traverse the array and swap elements to their respective positions.

• Time complexity is O(n) and space complexity is O(1).

Virtual functions are functions in a base class that can be overridden by derived classes to provide different implementations.

• Virtual functions are declared in a base class and can be overridden in derived classes.

• They allow polymorphism, where a pointer to a base class can invoke different derived class implementations.

• Virtual functions are resolved at runtime based on the actual object type.

• They are used to achieve runtime polymorphism and dynamic binding.

SDLC is a process followed by software development teams to design, develop and test high-quality software.

• SDLC consists of several phases including planning, analysis, design, development, testing, deployment, and maintenance.

• Each phase has its own set of deliverables and objectives.

• SDLC models include Waterfall, Agile, and DevOps.

• SDLC helps ensure that software is developed efficiently, on time, and within budget.

• SDLC also helps ensure that software meets the needs of stake...read more

Program to find all sibling nodes of a BST

• Traverse the BST and keep track of parent node

• If a node has the same parent as another node, they are siblings

• Recursively check left and right subtrees

• Use a queue or stack to implement level order traversal

Find the missing number in an array using DSA.

• Use XOR operation to find the missing number.

• Calculate XOR of all elements and XOR of 1 to n+1.

• Subtract the two XORs to get the missing number.

Find the length of longest increasing subsequence in an array.

• Use dynamic programming to solve the problem efficiently.

• Maintain an array to store the length of longest increasing subsequence ending at each index.

• Traverse the array and update the array for each index.

• Return the maximum value in the array as the length of longest increasing subsequence.

Find maximum of every window of size K in an array

• Iterate through the array and maintain a deque of indices of elements in the current window

• Remove indices from the front of the deque if they are outside the current window

• Remove indices from the back of the deque if their corresponding elements are smaller than the current element

• The front of the deque will always contain the index of the maximum element in the current window

An abstract class is a class that cannot be instantiated and is meant to be subclassed.

• An abstract class can have both abstract and non-abstract methods.

• It can provide a common interface for its subclasses.

• Subclasses of an abstract class must implement all the abstract methods.

• Abstract classes can have constructors.

• An abstract class cannot be instantiated directly, but its subclasses can be.

Kubernetes cluster can be exposed to the internet using various methods.

• One way is to use a LoadBalancer service type to expose the cluster to the internet.

• Another way is to use an Ingress controller to route traffic from the internet to the cluster.

• A third way is to use a NodePort service type to expose the cluster to the internet.

• It is important to secure the cluster by using authentication and authorization mechanisms.

• Tools like cert-manager can be used to manage SSL certi...read more

Code for reversing a linked list

• Create a new empty linked list

• Traverse the original linked list and insert each node at the beginning of the new list

• Return the new list

Code to find smaller prime number than input

• Start from input-1 and check if it's prime

• If yes, return it

• If not, continue checking smaller numbers until a prime is found

• If no prime is found, return -1

Create and delete a node in a linked list and print the updated list.

• Create a Node class with data and next pointer attributes

• Create a LinkedList class with head attribute and methods to add, delete and print nodes

• To delete a node, traverse the list and update the next pointer of the previous node to skip the node to be deleted

• Print the list by traversing and printing the data of each node

Find the kth smallest value in an unsorted array

• Sort the array and return the kth element

• Use quickselect algorithm to find the kth smallest element in O(n) time

• Build a min heap of size k and traverse the array to find the kth smallest element

CRUD stands for Create, Read, Update, and Delete. It refers to the basic operations performed on data in a database.

• CRUD is a fundamental concept in database management.

• Create refers to adding new data to the database.

• Read refers to retrieving data from the database.

• Update refers to modifying existing data in the database.

• Delete refers to removing data from the database.

• CRUD is used in many software applications, including web and mobile apps.

Implement binary search in a semi-infinite array.

• Start with the first element and keep doubling the index until the target element is less than the current element.

• Perform binary search on the subarray from the last doubled index to the current index.

• If the target element is not found, repeat the process by doubling the last index and searching again.

• Handle edge cases where the target element is at the first index or not present in the array.

Mutex is a synchronization mechanism used to prevent multiple threads from accessing shared resources simultaneously.

• Mutex stands for mutual exclusion.

• It is used to protect critical sections of code where multiple threads may try to access shared resources.

• Mutex allows only one thread to access the shared resource at a time.

• If another thread tries to access the resource while it is locked by a mutex, it will be blocked until the mutex is released.

• Mutex can be used in conjunct...read more

Swap 2 numbers without using a third variable

• Use the XOR operation to swap the numbers

• Assign the first number to the second number using XOR

• Assign the second number to the first number using XOR

Merge intervals and find second largest salary in SQL

• For merging intervals, sort them by start time and then iterate through the intervals to merge overlapping ones

• For finding second largest salary, use the SQL query: SELECT MAX(salary) FROM employees WHERE salary < (SELECT MAX(salary) FROM employees)

I have a Bachelor's degree in Computer Science.

• Bachelor's degree in Computer Science

• Completed courses in programming languages, algorithms, data structures, and software engineering

• Participated in various coding competitions and hackathons

Prims and Kruskal's algorithms are used to find the minimum spanning tree in a graph.

• Prims algorithm starts with a single vertex and adds the minimum weight edge to the tree until all vertices are included.

• Kruskal's algorithm starts with all vertices as separate trees and merges them by adding the minimum weight edge until all vertices are included.

• Both algorithms have a time complexity of O(E log V) where E is the number of edges and V is the number of vertices.

• Prims algorit...read more

To check if a linked list is circular or linear, we need to traverse the list and check if it loops back to a previous node.

• Traverse the linked list using two pointers, one moving one node at a time and the other moving two nodes at a time.

• If the faster pointer catches up to the slower pointer, then the list is circular.

• If the faster pointer reaches the end of the list without catching up to the slower pointer, then the list is linear.

Array methods in Javascript are built-in functions that can be used to manipulate arrays.

• Some common array methods are push(), pop(), shift(), unshift(), slice(), splice(), concat(), join(), indexOf(), and forEach().

• push() adds one or more elements to the end of an array.

• pop() removes the last element from an array.

• shift() removes the first element from an array.

• unshift() adds one or more elements to the beginning of an array.

• slice() returns a new array with a portion of the ...read more

Find unique character from a string and optimize it

• Use a hash table to store the frequency of each character in the string

• Iterate through the hash table to find the character with frequency 1

• If there are multiple characters with frequency 1, return the first one

• Optimization: Stop iterating through the hash table once a character with frequency 1 is found

Segmentation fault is a type of error caused by accessing memory that “does not belong to you.”

• It occurs when a program tries to access a memory location that it is not allowed to access.

• It is often caused by programming errors such as accessing an array beyond its bounds.

• It can also be caused by hardware problems such as faulty RAM or overheating.

• Segmentation faults can be difficult to debug because they often occur in low-level code.

• Examples of segmentation fault errors inc...read more

Find the second maximum number from an array of strings.

• Convert the array of strings to an array of integers.

• Sort the array in descending order.

• Return the second element of the sorted array.

Question about finding complexity of multiplying big integers.

• Big integers require more memory and processing power than regular integers.

• Multiplying two n-digit integers takes O(n^2) time using the standard algorithm.

• There are faster algorithms like Karatsuba and FFT which have lower complexity.

• The complexity of multiplying two n-digit integers using Karatsuba algorithm is O(n^log2(3)).

• The complexity of multiplying two n-digit integers using FFT algorithm is O(n*log(n)).

A database is a collection of organized data that can be easily accessed, managed, and updated.

• A database stores data in tables with rows and columns

• It allows for efficient data retrieval and manipulation

• Examples include MySQL, Oracle, and MongoDB

Sort function in C++ sorts elements in an array in ascending or descending order.

• The sort function is part of the library in C++.

• It takes two iterators as arguments, representing the beginning and end of the array to be sorted.

• By default, it sorts the array in ascending order, but a custom comparison function can be provided to sort in descending order.

• The time complexity of the sort function is O(n log n).

Smart Pointer is a class that provides automatic memory management for dynamically allocated objects.

• Smart pointers are used to prevent memory leaks in C++.

• They automatically delete the object they point to when it is no longer needed.

• There are two types of smart pointers: unique_ptr and shared_ptr.

• unique_ptr is used when there is only one owner of the object.

• shared_ptr is used when there are multiple owners of the object.

Explanation of linked list reversal and RabbitMQ

• Linked list reversal can be done iteratively or recursively

• Iterative reversal involves changing the pointers of each node to point to the previous node

• Recursive reversal involves calling the function recursively on the next node and changing its pointer to the current node

• RabbitMQ is a message broker that allows for asynchronous communication between applications

• It uses a publish-subscribe model where producers publish messages ...read more

Implementing 2 stacks with optional approach

• Two stacks can be implemented in a single array by dividing it into two halves

• Optional approach can be implemented by using a third parameter to indicate which stack to use

• Push and pop operations can be performed on both stacks independently

Spring MVC is a framework for building web applications, while Spring Boot is an opinionated framework for building standalone applications.

• Spring MVC requires more configuration and setup compared to Spring Boot

• Spring Boot provides a pre-configured environment with sensible defaults

• Spring Boot includes an embedded server, making it easier to deploy standalone applications

• Spring MVC is more suitable for building traditional web applications, while Spring Boot is better for mi...read more

To find a number from a singly linked list.

• Traverse the linked list and compare each node's value with the target number.

• If the target number is found, return the node.

• If the end of the linked list is reached without finding the target number, return null.

Find the first repeated element in an array of strings in O(n) time complexity.

• Create a hash table to store the frequency of each element.

• Traverse the array and check if the element is already present in the hash table.

• If it is present, return the element as the first repeated element.

• If no element is repeated, return null or -1.

• Example: ['apple', 'banana', 'orange', 'apple'] => 'apple'

Design an algorithm with less time complexity.

• Use efficient data structures like hash tables, binary trees, etc.

• Avoid nested loops and recursion if possible.

• Try to optimize the code by reducing redundant operations.

• Use dynamic programming to solve complex problems.

• Consider parallel processing for large datasets.

• Use built-in functions and libraries instead of writing custom code.

• Profile the code to identify bottlenecks and optimize accordingly.

Building Amazon requires a multi-faceted approach involving technology, logistics, and customer-centricity.

• Develop a robust e-commerce platform with a user-friendly interface

• Establish a vast network of warehouses and distribution centers for efficient delivery

• Invest in cutting-edge technology such as AI and machine learning for personalized recommendations

• Prioritize customer satisfaction through excellent customer service and easy returns

• Partner with third-party sellers to ex...read more

Convert an expression to post-fix notation.

• Start with an empty stack.

• Scan the expression from left to right.

• If the scanned character is an operand, output it.

• If the scanned character is an operator, pop two operands from stack, output them in post-fix notation and push the result back.

• Repeat until the end of expression.

The best days to buy and sell stocks depend on market trends and individual stock performance.

• Monitor market trends and stock performance

• Consider buying during market dips and selling during market highs

• Research historical data and patterns

• Consult with financial advisors

• Be mindful of taxes and fees

Ethernet is a networking technology used for LANs. Switches and hubs are devices used to connect multiple devices to a network.

• Ethernet is a protocol used for communication between devices on a network.

• A switch is a networking device that connects devices on a network and directs data to its intended recipient.

• A hub is a networking device that connects devices on a network and broadcasts data to all connected devices.

• Switches are faster and more efficient than hubs.

• Ethernet c...read more

A Load Balancer distributes incoming network traffic across multiple servers to improve performance and availability.

• It helps to avoid overloading a single server

• It improves responsiveness and availability of applications

• It can be hardware or software-based

• Examples include Amazon ELB, F5 BIG-IP, and NGINX

• It can also perform health checks on servers and route traffic accordingly