Microsoft Software Engineer interview questions

Campus recruitment. First there was a written round. MCQs were easy. Programming questions were 1) Print out the last 10 lines of a string. 2)Level wise printing of a binary tree. First Interview: 1)Convert "aaabbcccsss" to "a3b2c3s3" inplace. 2)Find if a linked list is circular Second Interview: 1)Two extra pointers in nodes of a BST, prev and next. Set them to inorder predecessor and successor respectively. Gave a nlogn average solution. Interviewer told me write code which took me nearly 25 minutes. Rejected after this round.