Most Asked Coding Interview Questions

How Do You Design A Chat Application Like Whatsapp Or Facebook Messenger

You have surely used WhatsApp and Facebook, right? No? If not let me tell you that a chat application allows you to send messages to your friend. Its a point to point connection.

You keep a friend list and see their status and chat with them. In WhatsApp, you can also connect groups but that is for advanced and experienced developers. At a minimum, you should provide a design to keep a friend list and send and receive messages from them.

If you need some tips then I suggest you check out Rocking System Design Course on Udemy, where you will find a whole case study to solve this problem.

9. How do you design a Twitter Clone?Twitter is a popular messaging service that lets you broadcast your messages to all your followers. You tweet and your followers see those messages, they can like or retweet.

Make sure you implement common features like followers, hashtag, tweet, delete, etc. If you going nowhere and stuck, you can follow the solution on System Design Interviews: Grokking the System Design Interview.

10. How to design a global video streaming service like YouTube or Netflix? While designing a video streaming service like Netflix or YouTube key thing is smooth streaming and buffering and functioning over low bandwidth connection, how do you manage those challenges.

11. How to design an ATM machine?An ATM machine allows a user to deposit and withdraw cash. It also allows a user to see his balance. How do you design such a system? What are your main challenges?

How To Remove Leading And Trailing Whitespaces From A String

Java String class contains two methods to remove leading and trailing whitespaces – trim, and strip. The strip method was added to the String class in Java 11. However, the strip method uses Character.isWhitespace method to check if the character is a whitespace. This method uses Unicode code points whereas the trim method identifies any character having codepoint value less than or equal to âU+0020â as a whitespace character. The strip method is the recommended way to remove whitespaces because it uses the Unicode standard.

String s = "  abc  def\t" s = s.strip System.out.println 

Since String is immutable, we have to assign the strip output to the string.

Programming Questions On Searching And Sorting

23) Write a program to sort numbers in place using quick sort? 24) Write a program to implement a binary search algorithm in Java or C++? 25) How do you sort Java objects using a Comparator? 26) Write code to implement Insertion Sort in Java?27) Write code to implement Bubble Sort in Java?Algorithm Design Manual by Steven Skiena

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Best Resources To Prepare System Design Interviews

If you need some more resources like online courses and guides and a few more questions to practice then you can check out these online courses and book to further sharpen your knowledge and crack any System design interviews.

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Thanks for reading this article so far. If you like these Software design and System Design interview questions then please share them with your friends and colleagues. If you have any questions or feedback then please drop a note.

P.S.- If you are looking for some free courses to learn Design Pattern and Software Architecture, I also suggest you check out the Java Design Patterns and Architecture course by John Purcell on Udemy. Its completely free, all you need to do is create an Udemy account to access this course.

Copy Linked List With Arbitrary Pointer

You are given a linked list where the node has two pointers. The first is the regular next pointer. The second pointer is called arbitrary and it can point to any node in the linked list. Your job is to write code to make a deep copy of the given linked list. Here, deep copy means that any operations on the original list should not affect the copied list.

def deep_copy_arbitrary_pointer:   #TODO: Write - Your - Code  return None

Click here to view the solution in C++, Java, JavaScript, and Ruby.

Runtime Complexity: Linear,

This approach uses a map to track arbitrary nodes pointed by the original list. You will create a deep copy of the original linked list in two passes.

• In the first pass, create a copy of the original linked list. While creating this copy, use the same values for data and arbitrary_pointer in the new list. Also, keep updating the map with entries where the key is the address to the old node and the value is the address of the new node.
• Once the copy has been created, do another pass on the copied linked list and update arbitrary pointers to the new address using the map created in the first pass.

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How Do You Find The Missing Number In An Array Of 1

A hiring manager may ask this question to determine your knowledge of array programming and its fundamental concepts. Interviewers often ask a question like this before moving on to more in-depth questions about duplicating arrays. Discuss how to calculate the number series properly in your response.

Example:”You can find the missing number in an array of 1-100 by applying the formula n/2 to the series and calculating the sum of the series.”

Print Balanced Brace Combinations

Print all braces combinations for a given value n so that they are balanced. For this solution, we will be using recursion.

The solution is to maintain counts of left_braces and right_braces. The basic algorithm is as follows:

left_braces count: 0right_braces count: 0if left_braces count is less than n:  add left_braces and recurse furtherif right_braces count is less than left_braces count:  add right_braces and recurse furtherstop recursing when left_braces and right_braces counts are both equal to n

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Linked List Based Programming Interview Questions

reversing a linked listlinked list23. How to find the middle element of a singly linked list in one pass?26. How to reverse a single linked list without recursion?29. How to find the 3rd node from the end in a singly linked list?recursion Visualizing Data Structures and Algorithms in Java30 linked list programming questions

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Design A Parking Lot Using Object

Cody Daig, Galvanize.

Cody Daig, Galvanize

What skillset is this testing for? Here were looking at, Can you think through how to take something thats not obviously an object at first, and turn it into a series of objects to accomplish what youre trying to accomplish? This will vary a little by language, but ultimately its a class. Its a problem to get you to think through and break down classes.

Sure, you have the parking lot and you have parking spaces. But if we have a programming need for this, we probably need to think through, is a space occupied?That means you have to have the concept of a class of a vehicle, and the vehicle has to occupy a space. You can have the concept of entrances, and parking lots can even have more than one floor. So it really comes down to whether you can take this problem and break it down and think through all of the possible things that need to be considered when building a parking lot.

Is this a good interview question? Its very common to have a question that is vague, but its also acceptable for the interviewee to come back and ask questions. What are you looking for out of this problem? Are we talking a parking lot at Walmart? Are we talking a parking lot with multiple floors? You can ask questions to determine how complex you need to make this. But its a very valid piece for them to just see your thought process and things that you might need to take into consideration.

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Give An Example Of A Time When You Worked With A Team To Solve A Problem

An interviewer might ask this question to determine your ability to work with a team and if you can add to their company culture. When answering this question, focus on the skills that would make you an asset to the company’s team and how you have used those skills to successfully complete team projects in the past.

Example answer:”In my prior role, I was a member of a team of developers working on an enterprise-class application to develop a customer relationship management system. Our team functioned by assigning each developer a different piece of code to write. After I finished writing the code assigned to me, I helped the team finish the project early by helping other developers work on their code.”

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Clone A Directed Graph

Given the root node of a directed graph, clone this graph by creating its deep copy so that the cloned graph has the same vertices and edges as the original graph.

Lets look at the below graphs as an example. If the input graph is G

We use depth-first traversal and create a copy of each node while traversing the graph. To avoid getting stuck in cycles, well use a hashtable to store each completed node and will not revisit nodes that exist in the hashtable. The hashtable key will be a node in the original graph, and its value will be the corresponding node in the cloned graph.

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Write A Code To Reverse A Number

#includeint main//To show the user valueprintf //after reverse show numbersprintf return 0 }
//Reverse of a number#include   using namespace std   //main programint main  while        //outputcout< < "Reversed Number: "< < reverse      return 0   }
public static void main
num = int)temp = numreverse = 0while num >  0:    remainder = num % 10    reverse =  + remainder    num = num // 10print)
Prepare For Coding Assessment
       
Its up to you to come to a coding interview fully prepared for technical assessment. I recommend at least three months of self-study to be successful. This includes choosing a programming language, reviewing the basics, and studying algorithms, data structures, system design, object-oriented programming, OS, and concurrency concepts.
Youll also want to prepare for behavioral interviews.
Its best to find or create an  Interview Prep Roadmap to keep yourself on track.
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What Is The Difference Between The Implementation Of Pre
Pre-order, postorder and in-order traversal are various ways of traversing in non-linear data structures like trees. Every tree has a root node and 2 child nodes . Each of these left and right nodes would again have one or 2 child nodes, and the process continues. The classification on traversal is made based on the path in which the root node, the left node, and the right node are traversed.





In Order Traversal  Left node, the root node, and right node.
Pre-Order Traversal  Root node, left node, and right node.
Post-Order Traversal  Left node, Right node, and the root node.
Write Code Of Perfect Number
#includeint main} //to condition is trueif//displayprintf  //to condition is falseelse //displayprintf return 0 }
#includeusing namespace std //main Programint main   //checking for perfect number    if         cout< <  num < < " is a perfect number."     else        cout< <  num < < " is not a perfect number."     return 0 }
import java.util.Scanner public class perfect_number_or_not//comparing whether the sum is equal to the given number or notifSystem.out.println elseSystem.out.println //closing scanner classsc.close }}
n = int)sump= 0for i in range: if: sump= sump + iif : printelse: print
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Can I Become An Expert In Programming Within 6 Months
While you can certainly master the basics, it is not a realistic timeframe to become a programming expert in six months. This is because there is such a wide range of programming languages, each with its own application and use cases. Your best bet is to choose a programming language to specialize in, such as Python or C, and learn as many code concepts as you can in the next six months. 





Programmers need to have a range of skills, including the ability to adopt new technologies, solve problems, and notice little details. These are skills you will continuously develop the more you practice programming.
Since youre hereNo one wakes up knowing how to code they learn how to code. Tens of thousands of students have successfully learned with our courses, like our Software Engineering Bootcamp. If youre a total newbie, our Software Engineering Career Track Prep Course will be a perfect fit. Lets do this!
About Kindra Cooper
Kindra Cooper is a content writer at Springboard. She has worked as a journalist and content marketer in the US and Indonesia, covering everything from business and architecture to politics and the arts.
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How Do You Reverse A String In Java
    Top 15 Python Coding Interview Questions with Solutions – Do it Yourself   
There is no reverse utility provided in Java. Hiring managers might ask this question to determine your knowledge of Java and your problem-solving skills. You can create a character array from the string and iterate it from the end to the beginning. You can append the characters to a string builder and finally return the reversed string.
Example answer:
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Common Coding Interview Questions You Should Know
Tammy Xu is a former Built In staff reporter covering software development and trends across the tech industry. A former software developer for Dow, she holds a masters degree in computer science from the University of Illinois Urbana-Champaign.
Tammy Xu is a former Built In staff reporter covering software development and trends across the tech industry. A former software developer for Dow, she holds a masters degree in computer science from the University of Illinois Urbana-Champaign.
Technical coding questions are some of the most intimidating aspects of the software development interview process. Though the questions may look quite different for different companies, most companies subject interviewees to some version of it.
Coding interview questions arent meant to be tools of terror. Each of the questions interviewers ask is trying to gauge something specific about candidates, whether its simple coding prowess, systems knowledge, familiarity with design principles, or just the ability to collaborate with others  including the interviewer.
Built In asked three individuals familiar with the software engineering recruitment process to talk about nine common coding interview questions and the skill sets they are measuring for. Questions were sourced from popular practice coding interview websites such as LeetCode, as well as coding interview prep textbooks.
How Do You Traverse A Binary Tree In Postorder Traversal Without Recursion
Move down to the leftmost node using the left pointer. While moving down, push root and roots right child to stack. Once you reach the leftmost node, print it if it doesnt have a right child. If it has a right child, then change the root so that the right child is processed before. 
The algorithm goes as follows:
1. Create an empty stack
2. Do the following while the root is not NULL:
 a) Push roots right child and then root to stack.
 b) Set root as roots left child.
3. Pop an item from the stack and set it as root.
 a) If the popped item has a right child and the right child is at the top of the stack, then remove the right child from the stack, push the root back and set root as roots right child.
 b) Else print roots data and set root as NULL.
4. Repeat steps 2 and 3 while the stack is not empty.
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Binary Tree Programming Questions
The binary tree data structure stores data hierarchically instead of in a linear fashion. A hiring manager may ask you questions about binary tree programming to determine how familiar you are with different tree data structures and popular traversing algorithms. Here are some common questions about binary tree programming algorithms:


How are leaves printed?


Can you traverse a binary tree in post-order traversal without recursion?


How do you implement a binary tree?


What is the depth-first search algorithm for a binary tree?


How do you traverse a binary tree in preorder without recursion?


What are the differences between preorder, in-order and post-order traversals?


What is a post-order traversal algorithm, and how do you use it?


What steps would you take to perform a binary search in a given array?


Problem Solving Interview Questions For Software Engineer Or Coder Jobs
       
Some programming interviews will build to some kind of practical, hands-on, or problem-solving demonstration to see how well you can improvise and bring together the major and minor programming concepts. 
Remember that the most important underlying skill for any type of programmer is the ability to think logically.
11 problem-solving questions for you to practice:
87. Heres an example of a problem involving random selection:
 Example
 If you had an array of 52 numbers, such as a deck of cards, it would be easy to choose one at random. Your task is to generate a number between 1 and 52 and use that as the index to your array. In other words, derive a system whereby a number or card is chosen at random from a set or deck with all numbers or cards equally probable.
88. Heres a more difficult variation:
 Example
Imagine you can neither see the whole set at once nor store it. In other words, youre not told how many total numbers there will be, and you are shown only one number at a time. You cannot store all the numbers you are shown, and you are only told when youve seen the final number of the set.
If you are allowed to store two numbers at most, can you respond with a random number, chosen in an equiprobable manner, from that one-at-a-time set or stream immediately upon being told the stream is complete?
89. Heres how to solve this problem:
 Example
Here are some other problems to work through:
91. Write a program to generate a random number from within a given range.
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