[mianos]

It may be only a very small part but not knowing how to invert a binary tree may well knock you out of the process. The process is designed to cull as many people as possible as early in the process as possible. It is accepted they might miss a few good people but it is more important that don't hire a bad one.

[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.

[milofeynman]

I don't know a single person across my org that will ever have to invert a binary tree. It's a hilarious problem that helps people who know it's a kind of problem asked, and hurts those who walk into it blind.

[fvdessen]

I think the point of fizzbuzz & inverting binary trees type of questions is to filter out people having issues solving them blind

[mianos]

I should have put a smiley after the bit about inverting a binary tree. :) It is a common joke. The rest is true though.