Yahoo Software Engineer interview questions

Was called directly onsite after I met them during the career fair and had 4 interview there. First interview was completely Algorithms based. Asked around 4-5 coding problems including problems that required one-armed quick sort, binary tree related questions, some bit manipulation and also they start of with 1 or 2 easy recursion based problems maybe to ease your nerves. Second interview was again algorithms based and the questions were simple but the last 20 mins the interviewer started discussion on java Internals and that got pretty complex. Third interview was the most fun. He asked me three question all pretty hard and especially the last one which which was to make any given string a palindrome by adding the minimum number of character. Well u have to use DP and if you have seen it before then its easy but it was first time i was solving this. So was fun and challenging. Last interview was some initial coding which involved hash map based solutions and then followed by design question.