The parent actually appears to have the quote both correct in content and attribution. Supposedly, someone else added the "off by one"[1][2][3]. That seems to be the extent of the Internet's knowledge on the quote, though the Skeptics link notes that there's nothing direct to the supposed originator.
This is one of those quotes where I feel there's more than one right answer. I like the addition of "off-by-one", and to make it a nice round three things, I usually use this version:
There are three hard things in computer science:
1. Naming things
2. 3. Concurrency
Cache Invalidation
4. Off-by-one errors
This is one of those quotes where I feel there's more than one right answer. I like the addition of "off-by-one", and to make it a nice round three things, I usually use this version:
[1]: https://twitter.com/timbray/status/506146595650699264[2]: https://skeptics.stackexchange.com/questions/19836/has-phil-...
[3]: http://martinfowler.com/bliki/TwoHardThings.html