Initally a recruiter make contact with me in LinkedIn. Then within a week, she send me a link for the online round. Once, I passed the online round, I was invited for the onsite interview. I got the result within 4 days that I am selected. I also have a pending result from Google. So did not yet decided. I can't describe the oroginal problem as I signed in NDA. But I feel I am so greatful to the leetcode community, so I am sharing my experience, it may be helpful to others.

Online Round:
I have two problem. One of the is similar to two sum problem, and another is related to heap. These are not two hard.

Onsite:
I have total 4 round, 3 techinical and 1 system design. LP questions are include in all the round. I have three LP questions in every round and those are very common questions.

Round 1:
One senior person, asked LP questions in first 20 minutes. Then asked me a binary tree traversal question. First I gave a trivial solution, then optimal one. I used global variable in the optimal solution. He asked me to solve it without using global variable, and I did it with passing a list as argument. After the solution I still have more than 15 minutes. But he didn't asked me any following questions. Instead, he explained one of his work experience related with tree traversal. That seems very strange to me.

Round 2:
System design round. Again, first 20 minutes, LP questions. Then asked me A/B testing related system design question. It was not that hard, but need to consider a lot of options. "Grooking the system design" course comes very helpful. I followed the pattern form the course to answer this question. The interviewer seems convinced.

Round 3:
Again, first 20 minutes, LP questions. Then asked me a variation merge k sorted list. It's not exact same question, but very similar.

Round 4:
Start with LP questions. Next asked me to implement a string encoder and decoder, thats similar to the RLE.

Result:
Got the offer to join as SDE 2, Seattle.

Preparation:
Mostly practiced on leetcode, solve around 600 problems. Also used Pramp for the real time practice. For the System Design, "Grooking the system design", was only resource.

Update
I also got the offer from Google, so I declined.