Location: Bay area
YOE: 5+

Round 1: Simulate a File system. Basically a trie question. You can add a file or directory. But you can't add an invalid path for /a/b/c/d.txt can not be added unless you have a, b, c as directories.

On-site
Round 1: System Design. Design Slack. Question regarding how will you mark the message read. API + storage layer (main focus), how will you push notifications. How will you show "someone is typing.." kinda feature.

Round 2: Bar raiser - Values and stuff. Explain one thing of your choice in less than 2 min or so.

Round 3: Pair programming - You are given a grid of size 6x7. Two player drop a coin from the top. They select the column (initially the selection is dumb or random) The coin will fall in the bottom most hole available in that column. The player wins if there are 4 coins of the same color in a row or column or diagonal (up or down)
Follow up: Add some intelligence in the players to select the column optimally.
How will you make the game generic so that it can check for 16 points in a row/column/diagonal
How will you handle a huge grid

Round 4: Pair Programming - You given data set in the form of list of <curr1 - curr2 - ask - bid> ask means how much curr2 do you have to spend to buy 1 unit of curr1 and bid is how much of curr2 will you get if you sell 1 unit of curr1.

Now given any two currencies x and y. Find the best conversion rate. Basically a graph problem you will have to traverse all paths from x to y because you want the best conversion rate.

follow up - Rather than hardcoding the data use two apis - 1.) https://api.pro.coinbase.com/products to get the id like USD-EUR aka currency pair and 2.) https://api.pro.coinbase.com/products/" + id + "/book to fetch the ask and bid price for each one of them. response = request.get(url) is enough to handle the GET calls + response.json() is enough to parse the response.

Result: Reject