[ohbtvz]

Let me get this straight. OP searched for an entry in a sorted list using dichotomic search. Okay... Any CS undergrad can do that. Is there something that I'm missing?

[dang]

Some important site guidelines, including:

"Don't be snarky."

"Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something."

https://news.ycombinator.com/newsguidelines.html

[civopsec]

It is famously difficult to implement binary search correctly.

[karmakaze]

How so, integer overflow? Not so famous that I'm aware.

[mason55]

> Not so famous that I'm aware

https://ai.googleblog.com/2006/06/extra-extra-read-all-about...

[kragen]

it took about ten years from the time of the first purported publication of a binary search algorithm for a correct algorithm to be published

it's an algorithm where it's easy to have off-by-one errors that lead to nontermination or incorrect results for certain inputs

integer overflow is also a problem on some platforms, especially java

[ilyt]

I doubt someone spent 10 years trying to implement a binary search.

I suspect it is as usual, someone made theoretical invention, then someone else looked at it years later and wrote implementation in evening or two

[kragen]

more likely there were a lot of correct implementations, but they got debugged after the initial publication, and then didn't publish the erratum

[amelius]

CS solved this problem, but not in such a way yet that we don't have to think about it anymore. If Python's dict implemented all of this under the hood then it could be called a solved problem.

[genericlemon24]

https://docs.python.org/3/library/bisect.html

[forgotusername6]

Does reading/seeking in a file that large make it harder?