I had a two-hour phone interview, followed by onsite interviews. I went through the process twice.

The first time was a decently good experience.

The second time was the worst interview experience of my life.

It's hard to believe plain luck matters the most.

Best of luck to the readers.

The interviewer forgot the question he wanted to ask. He then tried to make a statement about the question using incorrect words.

The question he intended to ask was: "Create a mirror reflection of a binary tree." However, he initially asked, "Do I know what a symmetric tree is?"

I explained what a symmetric tree is and how to check for symmetry.

The interviewer realized this was not the question he wanted to ask, and then he asked, "Let's create a symmetric (mirror) reflection of a tree."

I wrote the code to create the mirror reflection of the tree.

It seems he remembered the answer for "Invert a binary tree" and argued that my code to create a mirror would overwrite the left node's value. He did not understand that I was creating a new tree (the mirror tree), so there was no overwriting.

This led to a 20-minute, unproductive conversation, and the interviewer still did not grasp the simple code I wrote in 2 minutes.

The interviewer was a PhD, Sr. Staff with over 20 years of experience.

I felt miserable about my luck. I think this is why Google and Facebook still hold the most prestige.