I was invited for one interview, which lasted 2 hours. The interviewers were friendly and asked me general questions about my programming background (university projects) and previous internship.

They spent a lot of time going over the possibilities at Intel with me.

You have a queue of tasks, all of which take a different amount of time to complete. You have n machines that can handle these tasks simultaneously.

However, once each task finishes its initial mission, it must be further processed, and only one machine can do this processing.

Regardless of the time of the initial completion of the tasks, the last processing part must be done in order of the original queue. What data structure would you use to do this?