Hacker News: SeanSullivan86

New comment by SeanSullivan86 in "A software engineering interview question I like: computing the median"

SeanSullivan86 — Thu, 09 Jul 2026 02:32:51 +0000

Interesting approach, thanks. Yeah, I don't mind a question and conversation like that to start things off. But I do think getting into something a little deeper (which you also mentioned) later in the interview is important, too.

New comment by SeanSullivan86 in "A software engineering interview question I like: computing the median"

SeanSullivan86 — Thu, 09 Jul 2026 02:09:04 +0000

The overflow thing would be about computing the median of some sub-range of a sorted array. It is an often-quizzed thing that comes up as an edge case in binary search of a large array, but could apply to anything where you need to select the middle element of a sub-range of an array and the sum of the start/end indices could overflow.

I think the lore is that it was a bug in Java?'s binary search lib decades ago?

New comment by SeanSullivan86 in "A software engineering interview question I like: computing the median"

SeanSullivan86 — Thu, 09 Jul 2026 02:04:03 +0000

Huh, feels overly simple to me.

How about something like the beginnings of a spreadsheet engine?

Or.. count the number of distinctly shaped black regions in a bitmap image.

New comment by SeanSullivan86 in "YAML? That's Norway Problem"

SeanSullivan86 — Sat, 23 May 2026 03:47:29 +0000

Reminds me of some enum at my current employer, where all the US states have 2 letter codes, except Idaho is spelled out fully.

New comment by SeanSullivan86 in "Show HN: Number Gacha, a gacha game distilled to its essence"

SeanSullivan86 — Tue, 19 May 2026 06:30:31 +0000

Same. I think it's probably easier on a touch screen than with mouse, but I'm stuck on level 10 for now. Maybe it's intentionally frustrating. Need to finish this level to unlock the last number I think, but I guess I've I've sunk enough time into it and will let it rest there.

New comment by SeanSullivan86 in "All elementary functions from a single binary operator"

SeanSullivan86 — Mon, 13 Apr 2026 14:29:42 +0000

Wouldn't you also need to keep track of the stack's size, to know if there are leading zeros?

New comment by SeanSullivan86 in "10% of Firefox crashes are caused by bitflips"

SeanSullivan86 — Fri, 06 Mar 2026 07:00:29 +0000

Hmm, can someone educate me here? Why don't bit flips ever seem to impact the results of calculations in settings like big-data analytics on AWS?

Is it a difference between server hardware managed by knowledgeable people and random hardware thrown together by home PC builders?

New comment by SeanSullivan86 in "SectorC: A C Compiler in 512 bytes (2023)"

SeanSullivan86 — Sat, 07 Feb 2026 21:22:43 +0000

Why is it called a C Compiler if it's a subset of C?

New comment by SeanSullivan86 in "Performance Hints"

SeanSullivan86 — Fri, 19 Dec 2025 23:28:53 +0000

I'm aware of this to an extent. Do you know of any list of what degree of parallelization to expect out of various components? I know this whole napkin-math thing is mostly futile and the answer should mostly be "go test it", but just curious.

I was interviewing recently and was asked about implementing a web crawler and then were discussing bottlenecks (network fetching the pages, writing the content to disk, CPU usage for stuff like parsing the responses) and parallelism, and I wanted to just say "well, i'd test it to figure out what I was bottlenecked on and then iterate on my solution".

New comment by SeanSullivan86 in "Launch HN: Channel3 (YC S25) – A database of every product on the internet"

SeanSullivan86 — Wed, 20 Aug 2025 17:40:13 +0000

https://www.gs1.org/services/gdsn/global-data-model

As someone who has worked in e-retail, this catalog seems to have a lot of momentum.

New comment by SeanSullivan86 in "Shamelessness as a strategy (2019)"

SeanSullivan86 — Tue, 19 Aug 2025 02:10:33 +0000

Senior management doesn't like it, in my experience. But I agree it makes sense for many interactions.

New comment by SeanSullivan86 in "The Weight of a Cell"

SeanSullivan86 — Mon, 18 Aug 2025 17:53:48 +0000

What happens when something is put on the scale while it's sampling? Does the curve depend on properties of the scale, or just properties of the object and the manner in which it was put on the scale?

New comment by SeanSullivan86 in "White Mountain Direttissima"

SeanSullivan86 — Tue, 12 Aug 2025 03:16:30 +0000

I guess everyone has their own preferences, I just find this opinion surprising given the wealth of other hikes in the country.

As someone who grew up hiking in the White Mountains before moving to Washington, the mountains in Washington (and many places in the West) are just on a whole different level.

New comment by SeanSullivan86 in "Car has more than 1.2M km on it – and it's still going strong"

SeanSullivan86 — Sat, 09 Aug 2025 17:50:40 +0000

It's higher than average/median in the US, but certainly not exceptional. Pretty normal for certain groups of people. There's a huge gap in miles driven between urban and rural area. US average is something like 13-15k miles per year (for all driving, not just commute).

20,000 miles solely for commuting would be about 43 miles each way (if you work 235 days per year), which is obviously more unusual than 20k total miles driven from all sources.

New comment by SeanSullivan86 in "Inverted Indexes: A Step-by-Step Implementation Guide"

SeanSullivan86 — Sat, 26 Jul 2025 18:20:52 +0000

People (non-tech) don't tend to refer to "go to page 106" as using an index. The pages at the back of the book providing the word->page numbers lookup are commonly known as the book's "index"

New comment by SeanSullivan86 in "Inverted Indexes: A Step-by-Step Implementation Guide (2023)"

SeanSullivan86 — Sat, 26 Jul 2025 18:08:29 +0000

I've sometimes been confused by the term "inverted index". The example in this post feels like what I would just call an "index"... i.e documents indexed by the words they contain. Feels about the same as the index in the back of a physical book.

Is the distinction that an index on a multi-valued attribute is called an inverted index?