QBurst Technologies Senior Engineer Interview Questions and Answers

Closure is a function that captures the environment in which it was created, allowing it to access variables from that scope even after the scope has closed.

• Closure allows a function to access variables from its parent function even after the parent function has finished executing.

• It is created when a function is defined within another function and the inner function references variables from the outer function.

• Ex...read more

Memoization is a technique used in computer science to store the results of expensive function calls and reuse them when the same inputs occur again.

• Memoization helps improve the performance of algorithms by avoiding redundant calculations.

• It is commonly used in dynamic programming to optimize recursive algorithms.

• Example: Fibonacci sequence calculation using memoization to store previously calculated values.

SQL queries are essential for data manipulation and retrieval in relational databases.

• SELECT statement: Used to retrieve data from a database. Example: SELECT * FROM employees;

• JOIN clause: Combines rows from two or more tables based on a related column. Example: SELECT * FROM orders JOIN customers ON orders.customer_id = customers.id;

• WHERE clause: Filters records based on specified conditions. Example: SELECT * FR...read more

Yes, it is possible to work with multiple threads in core data.

• Use NSManagedObjectContextConcurrencyType to specify concurrency type

• Create a separate managed object context for each thread

• Use performBlock or performBlockAndWait to execute tasks on the correct context

• Merge changes from other contexts using NSManagedObjectContextDidSaveNotification

Implement a solution to find common elements in two arrays, improving efficiency step by step.

• 1. Simple Implementation: Use nested loops to compare each element of both arrays. Time complexity: O(n*m). Example: A = ['a', 'b'], B = ['b', 'c'] → common = ['b'].

• 2. Sort and Compare: Sort both arrays and use two pointers to find common elements. Time complexity: O(n log n + m log m). Example: A = ['a', 'b'], B = ['b', ...read more

Pseudo code for basic java programs

• Declare variables and assign values

• Write conditional statements

• Use loops for repetitive tasks

• Create functions for reusable code

• Use arrays and collections for storing data