Update knowledge.txt

knowledge.txt

@@ -84,4 +84,54 @@ Question: Give an example of a time you maintained accuracy under pressure.
 Question: Tell me about a time you advocated for a patient.
  Possible Answers: I requested social work support for a patient lacking family support. I escalated a denial of service to help a patient get covered treatment. I translated complex information so the patient could make an informed choice.
 Question: Describe a time when you had to follow strict procedures under time pressure.
- Possible Answers: I followed protocol during an emergency response drill. I administered medication during a critical situation by checklist. I handled an infection control incident by adhering to reporting standards
+ Possible Answers: I followed protocol during an emergency response drill. I administered medication during a critical situation by checklist.I handled an infection control incident by adhering to reporting standards
+ Question: What are the basic data types in your favorite programming language?
+ Possible Answers: Common basic data types include integers, floats, strings, and booleans. In Python, for example, we have int, float, str, bool, and more complex types like lists and dictionaries. Basic data types represent simple values like numbers and text.
+Question: Explain how a hash table works.
+ Possible Answers: A hash table stores key-value pairs using a hash function to compute an index. It allows for fast data retrieval by converting keys into array indices. Collisions happen when two keys hash to the same index, handled by chaining or open addressing.
+Question: What is the difference between stack and queue?
+ Possible Answers: A stack is Last-In-First-Out (LIFO), meaning the last element added is the first removed. A queue is First-In-First-Out (FIFO), meaning elements are removed in the order they were added. Stacks are used for things like function calls; queues are used for task scheduling.
+Question: How does memory management work in your programming language?
+ Possible Answers: Languages like Python use automatic garbage collection to free unused memory. In C/C++, developers manually allocate and free memory using malloc and free. Memory management ensures efficient use and prevents leaks or crashes.
+Question: What is recursion? Can you give an example?
+ Possible Answers: Recursion is when a function calls itself to solve a smaller instance of a problem. An example is calculating factorial: factorial(n) = n * factorial(n-1). It helps solve problems like traversing trees or solving puzzles.
+Question: Write a function to reverse a string.
+ Possible Answers: In Python, you can do: reversed_string = original_string[::-1]. Using a loop, you can iterate backwards and build the reversed string. Many languages have built-in functions to reverse strings efficiently.
+Question: How would you find the largest number in an unsorted array?
+ Possible Answers: Initialize a variable with the first element, then iterate through the array to find the max. You can use built-in functions like max() in Python. Sorting the array and taking the last element is another way, but less efficient.
+Question: Explain the difference between breadth-first search (BFS) and depth-first search (DFS).
+ Possible Answers: BFS explores nodes level by level using a queue. DFS explores as far as possible along each branch using a stack or recursion. BFS is good for shortest path; DFS is good for pathfinding and topology.
+Question: What is a binary search tree? How is it different from a binary tree?
+ Possible Answers: A binary search tree (BST) is a binary tree where left child nodes are smaller and right are larger. BSTs allow efficient searching, insertion, and deletion. A binary tree has no ordering constraints.
+Question: Describe the time complexity of common sorting algorithms (e.g., quicksort, mergesort).
+ Possible Answers: Quicksort average time complexity is O(n log n), worst case O(n²). Mergesort has consistent O(n log n) time complexity. Bubble sort and insertion sort have average O(n²) complexity and are inefficient for large datasets.
+Question: How would you design a URL shortener service?
+ Possible Answers: Use a database to map short codes to long URLs. Generate unique short codes, possibly using base62 encoding. Implement redirection logic and track usage statistics.
+Question: What are the key components of a scalable web application?
+ Possible Answers: Load balancers to distribute traffic. Database optimization and caching layers. Microservices architecture and containerization.
+Question: How would you approach designing a chat system?
+ Possible Answers: Use WebSocket connections for real-time messaging. Store messages in a database and implement user authentication. Consider scalability and message delivery guarantees.
+Question: Explain load balancing and why it is important.
+ Possible Answers: Load balancing distributes incoming network traffic across multiple servers. It improves availability and fault tolerance. Prevents any single server from becoming a bottleneck.
+Question: What is caching and how does it improve system performance?
+ Possible Answers: Caching stores frequently accessed data in fast storage to reduce latency. It reduces database load and speeds up response times. Common caches include memory caches like Redis or CDN caches.
+Question: What is normalization? Why is it important?
+ Possible Answers: Normalization organizes database tables to reduce redundancy and improve integrity. It involves decomposing tables into smaller related tables. Helps avoid update anomalies and maintain consistent data.
+Question: What’s the difference between SQL and NoSQL databases?
+ Possible Answers: SQL databases are relational and use structured schemas. NoSQL databases are non-relational, flexible, and handle unstructured data. NoSQL includes document, key-value, graph, and column-family stores.
+Question: How would you write a SQL query to find duplicate records?
+ Possible Answers: Use GROUP BY with HAVING COUNT() > 1 to identify duplicates. Example: SELECT column, COUNT() FROM table GROUP BY column HAVING COUNT(*) > 1. This groups rows and filters those with multiple occurrences.
+Question: What are ACID properties in databases?
+ Possible Answers: Atomicity ensures transactions are all-or-nothing. Consistency keeps database in a valid state. Isolation ensures concurrent transactions don't interfere. Durability guarantees committed transactions persist.
+Question: Explain indexing and how it affects query performance.
+ Possible Answers: Indexing speeds up data retrieval by creating quick lookup references. It can slow down write operations because indexes must be updated. Proper indexing improves query efficiency significantly.
+Question: What is SQL injection and how can you prevent it?
+ Possible Answers: SQL injection is an attack inserting malicious SQL code. Prevent it using prepared statements and parameterized queries. Validate and sanitize all user inputs.
+Question: Explain HTTPS and why it’s important.
+ Possible Answers: HTTPS encrypts data between client and server using SSL/TLS. It protects against eavesdropping and man-in-the-middle attacks. It ensures data integrity and user privacy.
+Question: What is cross-site scripting (XSS)?
+ Possible Answers: XSS is a security vulnerability that allows attackers to inject malicious scripts. It can be prevented by validating input and using content security policies. Sanitizing output to the browser is essential.
+Question: How do you securely store passwords?
+ Possible Answers: Passwords should be hashed using algorithms like bcrypt or Argon2. Never store plain text passwords. Use salts to add randomness to hashes.
+Question: What are some common vulnerabilities in web applications?
+ Possible Answers: SQL injection, cross-site scripting (XSS), cross-site request forgery (CSRF). Broken authentication and sensitive data exposure. Security misconfigurations and using vulnerable components.