chaoxu

13 ms·

121.
by chaoxu 12y ago
SEEKING WORK - Remote Available for any classical algorithm work. 1. Prove theorems about discrete structures. 2. Find algorithms for well formulated problems, or prove it's hard, along with references and proofs. (theoretically fast a
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by chaoxu 12y ago
"There is in university level maths books what looks like an almost wilful disregard for how people are actually taught mathematics at high school." The way the lower level courses are taught IS similar to high school math. Low le
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by chaoxu 12y ago
> Embarrassingly, years after a poorly-timed calculus course left me thinking I had to be able to prove the central limit theorem in order to use calculus Why would you need to prove central limit theorem in order to use calculus? What k
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by chaoxu 12y ago
Wikipedia has an article on this, http://en.wikipedia.org/wiki/Linear_equation_over_a_ring it would take a long time to read up the background to understand it, and I don't have the background to distill it to the
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by chaoxu 12y ago
I think it would work for all finite fields. One of the solutions to this IOI problem was solved that way, and it's not of the form GF(p) but it's GF(p^2). http://olympiads.win.tue.nl/ioi/ioi94/contest&#
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by chaoxu 12y ago
This problem can be generalized to the following graph light out game: Given a graph where each vertex is labeled 0 or 1. Each move flips all the bits on a vertex and all its neighbors. If you are given the end label configuration, find a s
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by chaoxu 12y ago
I know him because my independent study professor for analysis canceled his meeting with me because Simons took half of the math department for a cruise vacation. Well, I was happy. I didn't finish my hw that week. :)
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by chaoxu 12y ago
I applied there once, didn't even get an interview. I was from Stony Brook so I thought the Alumni connection would be useful... oh well...
129.
by chaoxu 12y ago
I have implemented KMP in Haskell. This version doesn't use any index! It is built purely functionally by realizing KMP's failure table is just a finite state automaton(well, almost...) However it is much longer than the C++ versi
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by chaoxu 12y ago
Also a graduate student in cs theory and was a BSMer(huh, I realized I attended your midwest theory day talk) There is a facebook group, computer science real talk. https://www.facebook.com/groups/500102603385910/
131.
by chaoxu 12y ago
For me, because I usually don't have to write a full fledged paper, only short math articles. I use Pandoc + pandoc-citeproc + mathjax and a Haskell code to make it more useful for writing math on the web. (basically, define theorem en
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APL Problem Solving Competition(dyalogaplcompetition.com)
45 points by chaoxu 12y ago|5 comments
133.
by chaoxu 13y ago
> If you let modulus number N be larger than n (e.g. n = 5 in my example, just let N = 6. Then 10 + x = 0 mod 6 will yield only one possible solution that is 2) then I think your solution will definitely work. That was entirely what I wa
134.
by chaoxu 13y ago
If we sum all the numbers we get n(n+1)/2 + x, where x is the duplicate number. Assume n(n+1)/2 = a mod n. If we did mod n addition the whole way, we have the result a+x mod n, and let that number be b. Claim: if a + x = b mod n,
135.
by chaoxu 13y ago
I feel what you asked is a really nice follow up question, as tricks to not get a overflow could be highly non-trivial. One can do addition mod n. As long as 2n doesn't overflow, you are good. You can further improve it by not using an
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A quick upper bound estimate on the number of states of the 2048 game.(mathb.in)
1 points by chaoxu 13y ago|0 comments
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by chaoxu 13y ago
One thing really useful would be allow one to embed this on their site. (just the code and annotation, and one can decide no one can comment or something). So it's like github gist, but with annotations. Sometimes I post codes with ann
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by chaoxu 13y ago
I posted some APL code, which is known to be hard to follow without lot of comments. I see how it can be useful. http://kurikku.com/s/52ef0f9ce4b0630f318682b3/apl-generate-p... I like how you can do nested comment