NVIDIA interview questions

The questions were mostly on RTOS and its concepts. Questions ranged from what is a semaphore, difference between semaphore and mutex, how would you design a system where 2 threads are trying to access a shared resource at the same time. FInally i got a dynamic problem - write a program which accepts user data of any type ( it can be a variable, array, structure, pointers etc) and sorts it. I did not know the solution to this question