[hintymad]

You don’t need leetcode to know how to invert a binary tree. You need solid foundation on algorithm and data structure, both of which are still relevant today.

[durovo]

I find it funny how inverting a binary tree is used as an example of a bad leetcode problem. This problem seems more like a fizzbuzz test, anyone who knows recursion should be able to solve it on their own.

[mips_avatar]

There’s a difference between being able to solve the problem given some thought, and being able to answer and program 2-3 of these problems in 45 minutes. The latter is what Facebook expects.

[jacobolus]

No idea about 'bad', but https://duckduckgo.com/?q=invert+binary+tree turns up nothing but interview prep sites.

[gifnamething]

But your slow reasoning and problem solving approach will be compared to another candidate's fast and savvy 'I've memorised this already' approach.