I was called up by a person who already worked as a Google Engineer. They asked a bunch of questions for which I was not fully prepared.

I think the most basic mistake I made was assuming that working full-time and evenings on coding would prepare me for any coding question within my area of expertise. Of course not!

The process involves reading a file of extreme size, a chunk at a time, and searching for the occurrence of a string within it.

The focus was on describing the algorithm and data structures used.