I was hired through a third party. The first round of interviews was held at the third party's company, and I was asked to do an online test. The test was about an hour long; it consisted of multiple-choice questions about programming and UML concepts. About a week later, I got a phone interview from PayPal, which lasted about 30 minutes. Questions were mostly about object-oriented programming concepts like polymorphism and inheritance. The last round of the interview was a group interview with two software engineers and one manager. I had to give a presentation about my last project, and they asked me programming questions. It lasted about three hours.

How to reverse a string without using a buffer.