Bloomberg Developer interview questions

The phone interview had 1 programming question: given a list of numbers where each number occurs twice except one, find the number. There was a follow-up question where exactly two numbers occurred once, every other number occurred twice, how will you find both the numbers. On-site questions were given and array of integers, return all valid ranges that exist within the array. The second interview on-site dealt for with C++ concepts like pointers, smart pointers and polymorphism.