Oracle Principal Software Engineer interview questions

In the 1 st round: (a) Find count of longest increasing subsequence in the given array of integers in O(n) time complexity (b) Find the list of prime numbers between 1 to n (c) Find highest salary of an employee given 3 tables: Employee ( E_ID, D_ID,E_NAME), DEPARTMENT ( D_ID and D_NAME) and SALARY ( E_ID and Salary) and highest salary of employee per department In the 2nd round: How will you design a system (using Restful Web Service and any other design algorithm) when there is a feed of events coming in for <Person> object type which queries a Server hub for a linux box. Each linux box has a specified limit on memory and CPU (not same for all) and you need to optimize each person with his/her usage and find the count of number of logins In the 3rd round: (a) Find the frequency of difference from the median for a given column in a database (b) Find the count of palindromes given a String

Explain how virtual memory works on a typical processor and why we use it.