Amazon Software Development Engineer II interview questions

I attended the interview in amazon development centre in Irvine, CA Consist of a telephonic Interview and an Onsite. Telephonic interview involved coding in Collab Edit and few data structures and OO questions. Telephonic interview questions : 1.Sort an array of string so that the anagrams are next to each other(coding question) 2.How to implement a file system( Just an idea) 3. basic OO questions Onsite: 1. Implement Poker game 2. Implement three stacks using single array. 3. Lunch Interview 4. Another bar raiser interview from seattle( Some binary Tree question) 5. HR - more than an hour. About previous accomplishments, strength , weakness, challenges, Problems etc. Prepare for this round with good examples