1. Got first 1:1 interview on campus. It was a pure algorithm test. Design a data structure to store a sparse 2D matrix containing only 0s and 1s, then write a function to add two such matrices.

I first proposed using an array to remember each 1's location, then realized it was quite expensive to perform the addition. With the interviewer's help, I arrived at using a hash table. I was then asked to write a hash function. It was quite challenging for me, but the interviewer was really nice and very helpful, pushing me to my limit.

1. Less than two weeks later, I was invited for an onsite interview in Sunnyvale. The interview started at 11 AM with a lunch with HR people, who provided some introduction to the company. This was followed by four 1:1 interviews, each focusing on: data structure, algorithm, OS/DB/web, and system design. Three out of the four interviewers had a heavy accent, making it difficult for me to understand them. Their questions were standard technical questions, such as:

• Insert/delete in a linked list
• Merge two sorted integer arrays into one
• What is a page table, virtual memory, schema? What related web experience do you have?
• Design a garage, what is a singleton?

Yahoo onsite interviews only occur on Mondays. The onsite interview experience was not very good. First, they flew me to Sunnyvale but only provided one night of hotel accommodation. This meant every candidate either ended up staying with friends for another night or had a very tight schedule. The lunch consisted of just tacos; many candidates didn't eat any food for lunch at all. My visit to the Yahoo office gave me the impression that it is a sad place to work. I decided not to work there the moment I entered the building; this was just a personal feeling.

I received a rejection email four days after the onsite interview.

Design a data structure to store a sparse 2D matrix which contains only 0 or 1. Then, write a function to add two such matrices.

• Insert/delete in a linked list.
• Merge two sorted integer arrays into one.

What is a page table, virtual memory, and schema? What related web experience do you have?

• Design a garage.
• What is a singleton?