Amazon Software Development Engineer SDE interview questions

I did an online assessment of AMZ. Received 2 questions in all. Each of them has 15 test cases. Only two cases are unlocked, which means you can see the specific testing inputs. But the others are locked, which only shows if you have passed the cases or not. I just got 6/15 and 0/15, and I received the rejection...

So far I have only done the phone screen and coding challenge the challenge was very hard standard leetcode problems like monotonic stacks and dynamic programming. Phone screen was very basic background and discussing which team i would be best fit for