I was contacted by a recruiter and asked to complete a two-hour coding challenge on HackerRank. The challenge asked relatively simple questions, and I got to choose the programming language.

Two or three days later, I was contacted again about scheduling a phone interview. The interview itself happened two weeks after that.

During the phone interview, I was asked questions about my resume and personal projects/experience. This was followed by an algorithms question, which I worked on in a shared document.

I was told a few days later that I would no longer be considered for the position.

Given an array with successive stock prices, provide an O(n) algorithm that finds the ideal single buy/sell indices.