I had 2 coding problems to solve in 35 minutes. First one is on moving average using sliding window size in an array (https://leetcode.com/problems/moving-average-from-data-stream/). Second one is on Dot product of sparse vectors (https://leetcode.com/problems/dot-product-of-two-sparse-vectors/). If you cannot finish the first one in 15 minutes, they move to the second one if you would prefer to. The second one was more like a discussion. Interviewer gave hints and tried to help in solving the problem but I should say both seemed to be NOT that hard but they are pretty tough if you haven't seen or practiced them before.