HubSpot contacted me about three weeks after I met a recruiter at a career fair. They warned me the process took only a week and so I should decide when to start the interview process such that I could respond within that period.

First, there was a coding challenge: two problems. One was easy, and the other appeared to be easy, but I only got one out of six tests to pass.

Nonetheless, they called me in to give me a tour of the workplace and asked me about some projects I had worked on. Then, they asked if I was in a position to accept the offer. I asked for another two weeks' delay (I had other interviews) and then accepted the offer.

Given an array of strings containing only lowercase letters, create a function that returns an array of those same strings. Each string should have its letters rearranged to form a palindrome, if possible. If a palindrome cannot be formed for a string, return -1 for that string.