Set of 12 Leetcode Questions on Linked List 👇👇

Easy :
21: Merge Two Sorted Lists
203: Remove Linked List Elements
206: Reverse Linked List
876: Middle of the Linked List

Medium :
19: Remove Nth Node From End of List
24: Swap Nodes in Pairs
116: Populating Next Right Pointers in Each Node
117. Populating Next Right Pointers in Each Node Il
237: Delete Node in a Linked List
707: Design Linked List

Hard :
23: Merge k Sorted Lists
25: Reverse Nodes in k-Group

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Top 40 commonly asked DSA questions :

𝗔𝗿𝗿𝗮𝘆𝘀 𝗮𝗻𝗱 𝗦𝘁𝗿𝗶𝗻𝗴𝘀:
1. Find the missing number in an array of integers.
2. Implement an algorithm to rotate an array.
3. Check if a string is a palindrome.
4. Find the first non-repeating character in a string.
5. Implement an algorithm to reverse a linked list.
6. Merge two sorted arrays.
7. Implement a stack using arrays/linked list.
8. Write a program to remove duplicates from a sorted array.

𝗟𝗶𝗻𝗸𝗲𝗱 𝗟𝗶𝘀𝘁𝘀:
1. Detect a cycle in a linked list.
2. Find the intersection point of two linked lists.
3. Reverse a linked list in groups of k.
4. Implement a function to add two numbers represented by linked lists.
5. Clone a linked list with next and random pointer.

𝗧𝗿𝗲𝗲𝘀 𝗮𝗻𝗱 𝗕𝗶𝗻𝗮𝗿𝘆 𝗦𝗲𝗮𝗿𝗰𝗵 𝗧𝗿𝗲𝗲𝘀 (𝗕𝗦𝗧):
1. Find the height of a binary tree.
2. Check if a binary tree is balanced.
3. Find the lowest common ancestor in a binary tree.
4. Serialize and deserialize a binary tree.
5. Implement an algorithm for in-order traversal without recursion.
6. Convert a BST to a sorted doubly linked list.

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Leetcode Questions you can check to Learn DSA from scratch 👇👇

1️⃣ Arrays: Data structures, such as arrays, store elements in contiguous memory locations. They are versatile and useful for a wide variety of purposes.
LeetCode Problems:
• Search in Rotated Sorted Array (Problem #33)
• Product of Array Except Self (Problem #238)
• Find the Missing Number (Problem #268)

2️⃣Two Pointers: In Two Pointers, two pointers are maintained in the collection and can be manipulated to solve a problem efficiently.
LeetCode problems:
• Trapping Rain Water (Problem #42)
• Longest Substring Without Repeating Characters (Problem #3)
• Squares of a Sorted Array (Problem #977)

3️⃣In-place Linked List Traversal: As an explanation, in-place traversal is a technique for modifying linked list nodes without using extra space.
LeetCode Problems:
• Remove Nth Node From End of List (Problem #19)
• Reorder List (Problem #143)

4️⃣Fast & Slow Pointers: This pattern uses two pointers to traverse a sequence at different speeds (fast and slow), often used to detect cycles or find a specific position in the sequence.
LeetCode Problems:
• Happy Number (Problem #202)
• Subarray Sum Equals K (Problem #560)
• Intersection of Two Linked Lists (Problem #160)

5️⃣Merge Intervals: This pattern involves merging overlapping intervals in a collection, often used in problems dealing with intervals or ranges.
LeetCode problems:
• Non-overlapping Intervals (Problem #435)
• Minimum Number of Arrows to Burst Balloons (Problem #452)

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How to become a better software developer:

1. Admit you don't know it all
2. Practice, practice, practice
3. Take every opportunity to learn
4. Accept your peers as a valuable source of knowledge
5. Embrace failure as a way to grow

Typical java interview questions sorted by experience


Junior
* Name some of the characteristics of OO programming languages
* What are the access modifiers you know? What does each one do?
* What is the difference between overriding and overloading a method in Java?
* What’s the difference between an Interface and an abstract class?
* Can an Interface extend another Interface?
* What does the static word mean in Java?
* Can a static method be overridden in Java?
* What is Polymorphism? What about Inheritance?
* Can a constructor be inherited?
* Do objects get passed by reference or value in Java? Elaborate on that.
* What’s the difference between using == and .equals on a string?
* What is the hashCode() and equals() used for?
* What does the interface Serializable do? What about Parcelable in Android?
* Why are Array and ArrayList different? When would you use each?
* What’s the difference between an Integer and int?
* What is a ThreadPool? Is it better than using several “simple” threads?
* What the difference between local, instance and class variables?

Mid
* What is reflection?
* What is dependency injection? Can you name a few libraries? (Have you used any?)
* What are strong, soft and weak references in Java?
* What does the keyword synchronized mean?
* Can you have “memory leaks” on Java?
* Do you need to set references to null on Java/Android?
* What does it means to say that a String is immutable?
* What are transient and volatile modifiers?
* What is the finalize() method?
* How does the try{} finally{} works?
* What is the difference between instantiation and initialisation of an object?
* When is a static block run?
* Why are Generics are used in Java?
* Can you mention the design patterns you know? Which of those do you normally use?
* Can you mention some types of testing you know?

Senior
* How does Integer.parseInt() works?
* Do you know what is the “double check locking” problem?
* Do you know the difference between StringBuffer and StringBuilder?
* How is a StringBuilder implemented to avoid the immutable string allocation problem?
* What does Class.forName method do?
* What is Autoboxing and Unboxing?
* What’s the difference between an Enumeration and an Iterator?
* What is the difference between fail-fast and fail safe in Java?
* What is PermGen in Java?
* What is a Java priority queue?
* *s performance influenced by using the same number in different types: Int, Double and Float?
* What is the Java Heap?
* What is daemon thread?
* Can a dead thread be restarted?

Source: medium.

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Learn Coding in 2024 👇👇

Programming Language: C++ / Java
Resources: Youtube, Geeksforgeeks

Week 1:
- Learn OOPs concepts
- Write simple codes Input/Output/Print/Loop
Platform: Visual Studio Code

Week 2-4:
- Practice Easy Level problems
- Daily 4 problems
Platform: Geeksforgeeks
Resource: Youtube / Online Course / Topmate

Week 5-8:
- Practice Easy & Medium Levels problems
- Start participating in Hackathons
Platform: Leetcode / Geeksforgeeks
Resource: Youtube / Online Course

Week 9-14:
- Develop additional skills like Web Development or Machine Learning
- Continue practicing DSA
Platform: Code Editors
Resource: Coursera / Youtube / Online Course

Week 15-18:
- Make projects to add to Resume
- Participate in Project / Coding Contests (Hackathons)
- Practice Medium & Hard level problems
Platform: HackerRank / Leetcode
Resource: Github / Leetcode

Week 19-20:
- Time your problem solving and increase speed.
- Start preparing for Interviews
- Start applying for Internships
Platform: LinkedIn / Email / Leetcode
Resources: InterviewBit, Glassdoor

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Java interview questions with answers 👇👇

1. What is Java?
Java is a high-level, object-oriented programming language developed by Sun Microsystems. It is platform-independent, meaning it can run on any device with the Java Virtual Machine (JVM) installed.

2. What is the difference between JDK, JRE, and JVM?
- JDK (Java Development Kit): It is a software development kit used for developing Java applications. It includes the JRE and development tools such as compilers and debuggers.
- JRE (Java Runtime Environment): It is an environment in which Java programs are executed. It includes the JVM and libraries necessary to run Java applications.
- JVM (Java Virtual Machine): It is an abstract machine that provides a runtime environment in which Java bytecode can be executed.

3. What are the main features of Java?
- Object-oriented: Java supports the concept of classes and objects.
- Platform-independent: Java programs can run on any device with a JVM installed.
- Simple: Java has a simple syntax and easy-to-use APIs.
- Secure: Java provides a secure runtime environment with features like bytecode verification and security manager.
- Multithreaded: Java supports multithreading, allowing multiple tasks to run concurrently.

4. What is the difference between an interface and an abstract class in Java?
- Interface: An interface in Java is a collection of abstract methods and constants. A class can implement multiple interfaces but cannot extend multiple classes.
- Abstract class: An abstract class in Java is a class that cannot be instantiated and may contain both abstract and concrete methods. A class can extend only one abstract class.

5. What is the difference between == and equals() method in Java?
- ==: The == operator in Java compares the memory addresses of two objects.
- equals(): The equals() method in Java compares the content of two objects. It is used to compare the values of objects.

6. What is a constructor in Java?
A constructor in Java is a special method that is used to initialize an object. It has the same name as the class and does not have a return type.

7. What is the difference between static and non-static methods in Java?
- Static method: A static method in Java belongs to the class rather than an instance of the class. It can be called using the class name.
- Non-static method: A non-static method in Java belongs to an instance of the class and can only be called using an object of the class.

8. What is the difference between checked and unchecked exceptions in Java?
- Checked exception: Checked exceptions are checked at compile time and must be handled by the programmer using try-catch or throws keyword.
- Unchecked exception: Unchecked exceptions are not checked at compile time and do not need to be handled by the programmer.

9. What is method overloading in Java?
Method overloading in Java is a feature that allows a class to have multiple methods with the same name but different parameters. The compiler determines which method to call based on the number and type of arguments passed.

10. What is method overriding in Java?
Method overriding in Java is a feature that allows a subclass to provide a specific implementation of a method that is already defined in its superclass. The overridden method must have the same name, return type, and parameters as the method in the superclass.

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Python interview questions with answers 👇👇

1. What is Python?
Python is a high-level, interpreted programming language known for its simplicity and readability. It supports multiple programming paradigms, including procedural, object-oriented, and functional programming.

2. What are the key features of Python?
- Easy-to-read syntax
- Dynamic typing
- Interpreted language
- Extensive standard library
- Object-oriented programming support
- Cross-platform compatibility

3. What is the difference between Python 2 and Python 3?
Python 2 and Python 3 are two major versions of the Python programming language. Some key differences include:
- Print statement: In Python 2, print is a statement, while in Python 3, it is a function.
- Unicode support: Python 3 handles strings as Unicode by default, whereas Python 2 uses ASCII strings.
- Integer division: In Python 3, the division of two integers results in a float, whereas in Python 2, it truncates the result to an integer.

4. What are the different data types in Python?
Python supports various data types, including:
- Integers
- Floats
- Strings
- Lists
- Tuples
- Dictionaries
- Sets
- Booleans

5. What is a Python decorator?
A decorator in Python is a design pattern that allows you to modify or extend the behavior of functions or methods without changing their code. Decorators are implemented using the @decorator_name syntax.

6. What is a lambda function in Python?
A lambda function in Python is an anonymous function defined using the lambda keyword. It is used for creating small, one-line functions without a name.

7. What is a list comprehension in Python?
List comprehension is a concise way to create lists in Python by iterating over an iterable and applying an expression to each element. It provides a more readable and efficient way to create lists compared to traditional loops.

8. How can you handle exceptions in Python?
Exceptions in Python can be handled using try-except blocks. The code that may raise an exception is placed inside the try block, and the exception handling logic is written in the except block.

9. What is the difference between deep copy and shallow copy in Python?
- Shallow copy: A shallow copy creates a new object but does not copy the contents of nested objects. Changes made to nested objects in the copy affect the original object.
- Deep copy: A deep copy creates a new object and recursively copies the contents of nested objects. Changes made to nested objects in the copy do not affect the original object.

10. How can you open and read a file in Python?
You can open and read a file in Python using the built-in open() function. Here's an example:

with open('filename.txt', 'r') as file:
    content = file.read()
    print(content)

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Common Programming Interview Questions

How do you reverse a string?
How do you determine if a string is a palindrome?
How do you calculate the number of numerical digits in a string?
How do you find the count for the occurrence of a particular character in a string?
How do you find the non-matching characters in a string?
How do you find out if the two given strings are anagrams?
How do you calculate the number of vowels and consonants in a string?
How do you total all of the matching integer elements in an array?
How do you reverse an array?
How do you find the maximum element in an array?
How do you sort an array of integers in ascending order?
How do you print a Fibonacci sequence using recursion?
How do you calculate the sum of two integers?
How do you find the average of numbers in a list?
How do you check if an integer is even or odd?
How do you find the middle element of a linked list?
How do you remove a loop in a linked list?
How do you merge two sorted linked lists?
How do you implement binary search to find an element in a sorted array?
How do you print a binary tree in vertical order?

Conceptual Coding Interview Questions

What is a data structure?
What is an array?
What is a linked list?
What is the difference between an array and a linked list?
What is LIFO?
What is FIFO?
What is a stack?
What are binary trees?
What are binary search trees?
What is object-oriented programming?
What is the purpose of a loop in programming?
What is a conditional statement?
What is debugging?
What is recursion?
What are the differences between linear and non-linear data structures?


General Coding Interview Questions

What programming languages do you have experience working with?
Describe a time you faced a challenge in a project you were working on and how you overcame it.
Walk me through a project you’re currently or have recently worked on.
Give an example of a project you worked on where you had to learn a new programming language or technology. How did you go about learning it?
How do you ensure your code is readable by other developers?
What are your interests outside of programming?
How do you keep your skills sharp and up to date?
How do you collaborate on projects with non-technical team members?
Tell me about a time when you had to explain a complex technical concept to a non-technical team member.
How do you get started on a new coding project?

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Free Resources To Crack Coding Interviews
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Coding Interview Prep FREE CERTIFIED COURSE

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Python Interview Questions and Answers

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Beginner's guide for DSA

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Java Interview Questions with Answers

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How to revise DSA:

- Look at a question
- 100% confidence If you instantly can remember the way it is solved, skip
- 70%, know the approach, try coding only the important bits and dry run against some cases
- 50%, having some confusion in head, code and run
- <30% treat it as new

Complete DSA Roadmap

|-- Basic_Data_Structures
| |-- Arrays
| |-- Strings
| |-- Linked_Lists
| |-- Stacks
| └─ Queues
|
|-- Advanced_Data_Structures
| |-- Trees
| | |-- Binary_Trees
| | |-- Binary_Search_Trees
| | |-- AVL_Trees
| | └─ B-Trees
| |
| |-- Graphs
| | |-- Graph_Representation
| | | |- Adjacency_Matrix
| | | └ Adjacency_List
| | |
| | |-- Depth-First_Search
| | |-- Breadth-First_Search
| | |-- Shortest_Path_Algorithms
| | | |- Dijkstra's_Algorithm
| | | └ Bellman-Ford_Algorithm
| | |
| | └─ Minimum_Spanning_Tree
| | |- Prim's_Algorithm
| | └ Kruskal's_Algorithm
| |
| |-- Heaps
| | |-- Min_Heap
| | |-- Max_Heap
| | └─ Heap_Sort
| |
| |-- Hash_Tables
| |-- Disjoint_Set_Union
| |-- Trie
| |-- Segment_Tree
| └─ Fenwick_Tree
|
|-- Algorithmic_Paradigms
| |-- Brute_Force
| |-- Divide_and_Conquer
| |-- Greedy_Algorithms
| |-- Dynamic_Programming
| |-- Backtracking
| |-- Sliding_Window_Technique
| |-- Two_Pointer_Technique
| └─ Divide_and_Conquer_Optimization
| |-- Merge_Sort_Tree
| └─ Persistent_Segment_Tree
|
|-- Searching_Algorithms
| |-- Linear_Search
| |-- Binary_Search
| |-- Depth-First_Search
| └─ Breadth-First_Search
|
|-- Sorting_Algorithms
| |-- Bubble_Sort
| |-- Selection_Sort
| |-- Insertion_Sort
| |-- Merge_Sort
| |-- Quick_Sort
| └─ Heap_Sort
|
|-- Graph_Algorithms
| |-- Depth-First_Search
| |-- Breadth-First_Search
| |-- Topological_Sort
| |-- Strongly_Connected_Components
| └─ Articulation_Points_and_Bridges
|
|-- Dynamic_Programming
| |-- Introduction_to_DP
| |-- Fibonacci_Series_using_DP
| |-- Longest_Common_Subsequence
| |-- Longest_Increasing_Subsequence
| |-- Knapsack_Problem
| |-- Matrix_Chain_Multiplication
| └─ Dynamic_Programming_on_Trees
|
|-- Mathematical_and_Bit_Manipulation_Algorithms
| |-- Prime_Numbers_and_Sieve_of_Eratosthenes
| |-- Greatest_Common_Divisor
| |-- Least_Common_Multiple
| |-- Modular_Arithmetic
| └─ Bit_Manipulation_Tricks
|
|-- Advanced_Topics
| |-- Trie-based_Algorithms
| | |-- Auto-completion
| | └─ Spell_Checker
| |
| |-- Suffix_Trees_and_Arrays
| |-- Computational_Geometry
| |-- Number_Theory
| | |-- Euler's_Totient_Function
| | └─ Mobius_Function
| |
| └─ String_Algorithms
| |-- KMP_Algorithm
| └─ Rabin-Karp_Algorithm
|
|-- OnlinePlatforms
| |-- LeetCode
| |-- HackerRank

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Top 10 Python Interview Questions

1. What is Python and what are its key features?
Python is a high-level, interpreted programming language known for its simplicity and readability. Its key features include dynamic typing, automatic memory management, a large standard library, and support for multiple programming paradigms (such as procedural, object-oriented, and functional programming).

2. What are the differences between Python 2 and Python 3?
Python 2 and Python 3 are two major versions of the Python programming language. Some key differences include:
- Python 3 has stricter syntax rules and is not backward compatible with Python 2.
- Python 3 has improved Unicode support and better handling of byte strings.
- Python 3 has some new features and improvements over Python 2, such as the print function being replaced by the print() function.

3. Explain the difference between list and tuple in Python.
- Lists are mutable, meaning their elements can be changed after creation, while tuples are immutable and their elements cannot be changed.
- Lists are defined using square brackets [], while tuples are defined using parentheses ().
- Lists are typically used for collections of items that may need to be modified, while tuples are used for fixed collections of items that should not change.

4. What is PEP 8 and why is it important in Python programming?
PEP 8 is the official style guide for Python code, outlining best practices for writing clean, readable, and maintainable code. Following PEP 8 helps ensure consistency across projects, makes code easier to understand and maintain, and promotes good coding habits within the Python community.

5. How do you handle exceptions in Python?
Exceptions in Python can be handled using try-except blocks. The code that may raise an exception is placed within the try block, and any potential exceptions are caught and handled in the except block. Additionally, you can use the finally block to execute cleanup code regardless of whether an exception occurs.

6. What is a decorator in Python and how do you use it?
A decorator in Python is a function that takes another function as input and extends or modifies its behavior without changing its source code. Decorators are typically used to add functionality to functions or methods, such as logging, authentication, or performance monitoring. To use a decorator, you simply place the "@decorator_name" above the function definition.

7. Explain the difference between '==' and 'is' in Python.
The '==' operator checks for equality of values between two objects, while the 'is' operator checks for identity, meaning it compares whether two objects refer to the same memory location. In other words, '==' checks if two objects have the same value, while 'is' checks if they are the same object.

8. How do you create a virtual environment in Python?
You can create a virtual environment in Python using the venv module, which is included in the standard library. To create a virtual environment, you run the command "python -m venv myenv" in your terminal or command prompt, where "myenv" is the name of your virtual environment. You can then activate the virtual environment using the appropriate command for your operating system.

9. What is the difference between a shallow copy and a deep copy in Python?
A shallow copy creates a new object but does not recursively copy nested objects within it, meaning changes to nested objects will affect both the original and copied objects. A deep copy creates a new object and recursively copies all nested objects within it, ensuring that changes to nested objects do not affect the original object.

10. How do you handle file I/O operations in Python?
File I/O operations in Python can be performed using built-in functions such as open(), read(), write(), close(), and more. To read from a file, you open it in read mode ('r') and use functions like read() or readline(). To write to a file, you open it in write mode ('w') or append mode ('a') and use functions like write() or writelines().

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Top 10 Java Interview Questions & Answers

1. What is Java and what are its key features?
Java is a high-level, object-oriented programming language that is designed to run on any platform. Its key features include platform independence, automatic memory management, strong type checking, and support for multithreading.

2. What is the difference between JDK, JRE, and JVM?
- JDK (Java Development Kit) is a software development kit that includes tools for developing, debugging, and monitoring Java applications.
- JRE (Java Runtime Environment) is a runtime environment that allows you to run Java applications. It includes the JVM (Java Virtual Machine) and necessary libraries.
- JVM (Java Virtual Machine) is an abstract machine that executes Java bytecode. It provides platform independence by running the same bytecode on different platforms.

3. What are the differences between abstract classes and interfaces in Java?
- An abstract class can have both abstract and non-abstract methods, while an interface can only have abstract methods.
- A class can extend only one abstract class, but it can implement multiple interfaces.
- An abstract class can have instance variables, while an interface cannot.
- An abstract class can provide default implementations for some methods, while an interface cannot.

4. What are the access modifiers in Java?
Java has four access modifiers:
- public: accessible from anywhere
- private: accessible only within the same class
- protected: accessible within the same package or subclasses
- default (no modifier): accessible within the same package

5. What is the difference between a class variable and an instance variable in Java?
- A class variable, also known as a static variable, is shared among all instances of a class. It is declared with the static keyword and is accessed using the class name.
- An instance variable is unique to each instance of a class. It is declared without the static keyword and is accessed using the instance name.

6. What is the difference between method overloading and method overriding in Java?
- Method overloading occurs when multiple methods in the same class have the same name but different parameters. The compiler determines which method to call based on the number and types of arguments.
- Method overriding occurs when a subclass provides a different implementation of a method that is already defined in its superclass. The method in the subclass must have the same name, return type, and parameters as the method in the superclass.

7. What is a constructor in Java?
A constructor is a special method that is used to initialize objects of a class. It has the same name as the class and does not have a return type. Constructors are called automatically when an object is created using the new keyword.

8. What are exceptions in Java and how do you handle them?
Exceptions are events that occur during the execution of a program that disrupts the normal flow of instructions. In Java, exceptions are represented by objects. They can be handled using try-catch blocks. The code that may throw an exception is placed within the try block, and any potential exceptions are caught and handled in the catch block.

9. What is multithreading in Java?
Multithreading is a feature of Java that allows multiple threads of execution to run concurrently within a single program. Each thread represents an independent flow of control, allowing for parallel execution of tasks. Multithreading can improve performance by utilizing available CPU resources effectively.

10. What is the difference between ArrayList and LinkedList in Java?
- ArrayList is implemented as a resizable array, while LinkedList is implemented as a doubly linked list.
- ArrayList provides fast random access to elements using indexes, while LinkedList provides fast insertion and deletion at both ends.
- ArrayList uses more memory than LinkedList because it needs to allocate memory for a fixed-size array, while LinkedList only needs to allocate memory for each element and its references.

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Top coding interview questions & answers Part-1 👇👇

1. What is the difference between a stack and a queue?
A stack is a data structure that follows the Last-In-First-Out (LIFO) principle, meaning that the last element added is the first one to be removed. A queue, on the other hand, follows the First-In-First-Out (FIFO) principle, where the first element added is the first one to be removed.

2. Explain the concept of recursion.
Recursion is a programming technique where a function calls itself to solve a problem. It involves breaking down a complex problem into smaller sub-problems until a base case is reached, which allows the function to stop calling itself and start returning values.

3. What is the time complexity of various sorting algorithms?
Some common sorting algorithms and their time complexities are:
- Bubble Sort: O(n^2)
- Insertion Sort: O(n^2)
- Selection Sort: O(n^2)
- Merge Sort: O(n log n)
- Quick Sort: O(n log n)
- Heap Sort: O(n log n)

4. What is the difference between an abstract class and an interface?
An abstract class can have both implemented and unimplemented methods, while an interface can only have unimplemented methods. A class can extend only one abstract class but can implement multiple interfaces.

5. What is the difference between a deep copy and a shallow copy?
A shallow copy creates a new object that references the same memory locations as the original object, while a deep copy creates a new object with its own memory and copies the values from the original object.

6. Explain the concept of polymorphism.
Polymorphism is the ability of an object to take on many forms. It allows objects of different classes to be treated as objects of a common superclass. This enables code to be written that can work with objects of different classes, as long as they share a common interface or superclass.

7. What is the difference between an instance variable and a static variable?
An instance variable belongs to an instance of a class and has separate copies for each instance. A static variable, on the other hand, belongs to the class itself and is shared by all instances of that class.

8. How does garbage collection work in Java?
Garbage collection in Java automatically frees up memory by deallocating objects that are no longer reachable or in use. The Java Virtual Machine (JVM) keeps track of all objects and their references, and periodically identifies and removes objects that are no longer needed.

9. Explain the concept of encapsulation.
Encapsulation is the practice of hiding internal details of an object and providing access to its functionality through well-defined interfaces. It helps in achieving data abstraction, data hiding, and code modularity.

10. What is the difference between a linked list and an array?
An array is a fixed-size data structure that stores elements in contiguous memory locations, allowing for random access using indices. A linked list, on the other hand, is a dynamic data structure where elements are stored in separate nodes that contain references to the next node, allowing for efficient insertion and deletion but slower random access.

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Top coding interview questions & answers Part-2 👇👇

11. What is the difference between an instance method and a static method?
An instance method operates on an instance of a class and can access instance variables and methods. A static method belongs to the class itself and can only access static variables and methods.

12. Explain the concept of inheritance.
Inheritance is a mechanism in object-oriented programming where one class inherits properties and behaviors from another class. The class being inherited from is called the superclass or base class, while the class inheriting is called the subclass or derived class. Inheritance allows for code reuse and promotes code organization.

13. What is the difference between stack memory and heap memory?
Stack memory is used for storing local variables and function calls, while heap memory is used for dynamically allocated memory using keywords like "new" or "malloc". Stack memory is managed by the compiler, while heap memory must be managed manually by the programmer.

14. What is a hashtable and how does it work?
A hash table (or hash map) is a data structure that allows for efficient insertion, deletion, and retrieval of key-value pairs. It uses a hash function to map keys to an index in an array, where values are stored. Collisions can occur when multiple keys map to the same index, which can be resolved using techniques like chaining or open addressing.

15. Explain the concept of deadlock.
Deadlock occurs when two or more processes are unable to proceed because each is waiting for a resource held by another process, resulting in a circular dependency. Deadlocks can be prevented by using techniques like resource allocation graphs, deadlock avoidance algorithms, or by implementing mechanisms like locks or semaphores.

16. What are some advantages of using object-oriented programming?
Advantages of object-oriented programming include code reusability, modularity, encapsulation, easier maintenance and debugging, improved code organization, and increased productivity through abstraction and polymorphism.

17. What is dynamic programming?
Dynamic programming is an algorithmic technique where complex problems are broken down into simpler overlapping subproblems, which are solved once and their solutions are stored for future reference. This technique helps avoid redundant computations and improves efficiency.

18. How does binary search work?
Binary search is an efficient algorithm for finding a target value within a sorted array. It compares the target value with the middle element of the array and narrows down the search space by half with each comparison until the target value is found or determined to be absent.

19. What are some common data structures used in computer science?
Some common data structures include arrays, linked lists, stacks, queues, trees (binary trees, AVL trees, etc.), heaps, hash tables, graphs, and sets.

20. Explain the concept of Big O notation.
Big O notation is used to describe the performance or complexity of an algorithm in terms of its input size. It represents the upper bound or worst-case scenario of an algorithm's time or space complexity. For example, O(1) represents constant time complexity, O(n) represents linear time complexity, O(n^2) represents quadratic time complexity, etc.

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