The interview lasted 2 hours. It began by describing what they do, then what I did in my professional past. They were very nice and really tried to help me succeed in the interview.

1. Implement alloc and free functions in C. The alloc function should always return a pointer to a 1KB memory chunk. The free function releases this memory chunk. You cannot use malloc, calloc, realloc, or free.

2. You need to implement a timer module that has a function timer. This function gets a time and a function pointer as input and calls the function when the time expires. What is the best data structure to use to get the next time in O(1)?