Harvey Software Engineer Interview Experience — A File System Design Screen With a Confusing Interviewer

The file system question that's been going around the forum. Here's my report.

Similar to a file system — implement two functions:

• addFile(String path): given a string like "path/to/somewhere/file.txt", store this file.
• getFile(String path): given "path/to/somewhere", return the content of file.txt; given "path/to", return the folder "somewhere".

There wasn't much of a self-introduction, we jumped right in. The interviewer was American, but his English was honestly hard to follow. He explained the problem once and I didn't catch it, so I just read it myself — pretty blunt intro. I just added a dict of dict and passed it down level by level, that's it.

Follow-up 1: each level can have at most 5 things (including folders and files) — once the current level's keys exceed 5, you can't add a new folder or file, even for just one new path. Just brute-force count the keys.

Follow-up 2: if there's a duplicate name, you need to handle it the way an OS does — file.txt, file(1).txt, file(2).txt. Just parse it (split around the ".") and maintain a counter that increments. One test case was add(file.txt), add(file.txt), add(file(1).txt), and the expected result was file.txt, file(1).txt, file(1)(1).txt. The interviewer struggled with this test case himself for a while, then after running it asked me if I understood what these test cases were checking. This requirement was never mentioned the whole time — he didn't explain when I asked, and he didn't say anything while he was fumbling through writing it either (how was I supposed to know what he wanted?). But my answer was correct.

There was also a follow-up on how to tell if two files are the same. Thanks to the forum write-ups, I'd prepared for this one — I answered with file hashing, like SHA-256 and MD5.

Passed.