Pure Storage - Rejected

Hi guys,

I gave interview for pure storage.

Was sent a rejection email after the first 2 rounds.

First Round

This was a more theoretical round about concurrency and other concepts of multi threading and handling parallelism. The interviewer was interested in how you approach problems with high concurrency.

Question -

Given a system that has one event and multiple listeners, design and implement a mechanism for the listeners to hear about the event. We want to implement a callback mechanism that allows listeners to register a function that will be invoked when the event fires. The API functions are register_callback and event_fired.

                                                 event_fired()
                                                      |
                                                      |
 ----------------------------------------------------------------------------->time
        |                         |                  cb1()                 |
        |                         |                  cb2()                 |
register_callback(cb1)    register_callback(cb2)   cb3()      register_callback(cb3)

2nd Round - Coding Round

Implement an unordered set. The value of elements will be 0 to n - 1 where n is the size of the set.