PayPal Software Development Engineer interview questions

I applied through my college.we had 4 rounds.1st round was an online test(20 apti+ 2 programming questions) for 1 hr.Each round was an elimination process.In round 2,they asked to explain the code that I had executed in round 1.Later questions were asked on data structures,Strings and few other questions with some constraints.Round 3 is completely based on my projects and other aceivements.The resume was scanned completely.Round 4 was a HR round.