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Bloody
Mar 3, 2013

we are imbeciles

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Bloody
Mar 3, 2013

a canonical easy to check hard to solve is any cryptographic hash

Bloody
Mar 3, 2013

the traveling salesman equivalent would be what is the shortest input that gives the correct hash


or, the other way around, traveling salesman is asking two questions: what's the shortest possible path, and what is one of those paths. checking that one of those paths is that length is easy but checking if it's the shortest possible is hard in the different kinda way


I think

Bloody
Mar 3, 2013

A Pinball Wizard posted:

how is polynomial time defined? im guessing "in one lifetime" isn't an actual si unit.

broadly it's the category of O(n^K) where k is basically just the number of nested loops your algorithm needs

Bloody
Mar 3, 2013

brute forcing traveling salesman, on the other hand, is O(n!) aka get hosed

Bloody
Mar 3, 2013

Silver Alicorn posted:

what if we made a computer so vast and efficient, it could simulate the entire universe faster than the universe itself existed?

information theory would show up and say "no" and then it wouldn't work

Bloody
Mar 3, 2013

LP0 ON FIRE posted:

i can tell you this: photosynthesis REALLY hates the color green for some reason and throws that poo poo out the window back into our eyes for us to see

lol yeah whats up w/ that

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Bloody
Mar 3, 2013

LP0 ON FIRE posted:

i don't know if i like the video.. he mentions sorting. checking sorting can be done in polynomial time, but actually sorting - isn't that np?

didnt watch the video, but sorting is n log n which is better than most polynomials

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