I had one coding phone interview, and I was invited for an on-site interview at Palo Alto. The process was quite fast.

The on-site interview consisted of four sessions:

• Two coding interviews
• One system design interview
• One behavioral and research experience interview

(These happened in this order, with a lunch break in the middle.)

The on-site interviews took place in a tiny 2-square-meter room. The room temperature was unadjustable, and it became too hot and stuffy inside. It felt almost like a torture room.

During my first coding interview, while I was writing code on the board, the interviewer sat at the table and played with his phone for most of the interview. I was thinking out loud and explaining my thought process, but he did not seem to be listening to me at all. When I asked a question, he responded with "Huh?". He was rude and lacked manners.

The second coding interviewer was much nicer. He stood up with me the whole time while I was coding on the board, followed my progress, and helped me along. This is how it should be.

The third interviewer arrived 5-10 minutes late, in a hurry, and was quite arrogant. Near the end of the system design interview, he asked me a question. I answered, but he did not seem satisfied. He then said, "You could do X, but anyway, we do not have time left." X is a technical term I had not considered.

Two interviewers were East Asian, one was South Asian, and one was Asian-American. It felt like I was in Asia.

Also, definitely do not dress up for this interview; jeans are more than enough. One of my interviewers was wearing sweatpants and a t-shirt.

1. You have a string consisting of open and closed parentheses, but parentheses may be imbalanced. Make the parentheses balanced and return the new string.

2. You have a string of numbers, e.g., 123. You can insert a + or - sign in front of every number, or you can leave it empty. Find all the different possibilities, make the calculation, and return the sum.

For example: +1+2+3 = 6 +12+3 = 15 +123 = 123 +1+23 = 24 ... -1-2-3 = 6 ... Return the sum of all the results.

1. How do you design Google Search autocomplete?

2. Classic behavioral questions.