https://bintanvictor.wordpress.com/2018/04/07/check-array-of-0-to-n-nasdaq/ is the Nasdaq question. It includes a link to my solution in github. I came up with my own solution. Then I tried your solution found online.
https://bintanvictor.wordpress.com/2018/04/10/check-array-can-be-preorder-bst-walk/ is another interview question. I tried my own and came up with a “better” solution.
If I don’t try my own solution, I would not learn a lot, and I would not have fun implementing my own idea (even if not optimal).
I also find it hard to absorb then remember clever solutions I found online, such as the maxRectangle.
Solving problems myself also grows my confidence when facing unfamiliar problems. I do read online solutions when I have no clue. confidence-build`: another reason y I don’t look at Leetcode answer
By the way, one advantage of my solution is — it can identify the missing numbers, all within O(N) time and O(1) space.