Thoughtwin IT Solutions Interview Questions and Answers

Convert a given string into sub-strings based on the number of rows in a zig-zag pattern and display as a single string.

• Create an array of strings with the number of rows specified

• Iterate through the input string and distribute characters in a zig-zag pattern

• Concatenate the sub-strings row by row to form the final output string

Count the continuous unique characters in a given string.

• Iterate through the string and keep track of the current character and its count

• If the current character is different from the previous one, print the count and reset it

• Handle both uppercase and lowercase characters separately

Use hash set to track unique elements while iterating through array and modify array in-place

• Iterate through array and add elements to hash set to track unique elements

• Modify array in-place by removing duplicates using hash set

• Return the size of the hash set as the number of unique elements

Node.js event driven architecture is a non-blocking, asynchronous model where events trigger callbacks.

• Node.js uses an event loop to handle asynchronous operations.

• Callbacks are registered for specific events and executed when the event occurs.

• Event emitters in Node.js trigger events that are handled by listeners.

• Example: Reading a file asynchronously in Node.js using fs module.

Multiple choice questions on NodeJS internals

• Node.js is an open-source, cross-platform JavaScript runtime environment that executes JavaScript code outside of a web browser.

• It uses the V8 JavaScript engine from Google, which compiles JavaScript directly into machine code.

• Node.js has a non-blocking, event-driven architecture that makes it lightweight and efficient for handling I/O operations.

• Common Node.js internals topics include event loop, modules, buffers, streams, and err...read more

Binary search is a divide and conquer algorithm that efficiently finds the target value within a sorted array.

• Divide the array in half and compare the target value with the middle element

• If the target value is smaller, search the left half. If larger, search the right half

• Repeat the process until the target value is found or the subarray is empty