Did anyone do any interviews with LinkedIn recently? What type of questions were asked?
It really depends on your experience and the role you are applying for.
More Senior Roles have easy to medium complexity algorithm questions during the Phone Interviews.
Most likely, using a Map or a Stack or a Queue, or a combination of two should help solve the problem.
What is more important than solving the problem, is asking clarifying questions. What happens to Duplicate inputs, what is expected behavior for certain edge-cases, upper-bounds and lower-bounds of the inputs, etc. Being more vocal is more important than printing an answer to the problem. They are genuinely looking for good Engineers that can work with other Engineers. Stay focused, and brush up your Algorithms with run-time complexities.