PayPal Risk Engineer interview questions

This is a summer intern interview. First, you should pass the paper technical test. The test is a little bit difficult if you never exercise algorithms coding like on site Leetcode. If you pass the paper test, you will get a phone technical interview, just a couple of simple programming questions, and an interesting algo. design question, the interviewer will hint on you if you can not catch up with an idea. After the phone interview, you will have two round two to one onsite interviews. I did not pass the first round. In the first round , interviewer will ask you some programming questions, a little harder than the phone interview. Then you will asked to design an OO problem, use UML. At last , I met a brainteaser question, which is about throwing two eggs...