David Eppstein
11011110.livejournal.com · Personal blog · on HN since 2009
David Eppstein, a computer science professor, blogs about algorithms, graph theory, data structures and complexity.
What HN saysHN commenters link his posts on cuckoo filters, A* as Dijkstra with modified weights, Sudoku complexity and Algorithm X.
15HN people shared it
5linked it in comments
16stories submitted
421story points
10 years agolast shared
2009people per year2026
Most-shared posts
- 1Reweighting a graph for faster shortest paths3 people · 62 points · first shared 2009 · 5 comments on HN
- 2Cuckoo filters and their analysis2 people · 89 points · first shared 2016 · 8 comments on HN
- 3Top ten algorithms preprints of 20121 people · 70 points · first shared 2013 · 5 comments on HN
- 4Fast algorithm for finding RSA keys with shared prime factors1 people · 62 points · first shared 2012 · 4 comments on HN
- 5Best algorithms preprints of 20111 people · 49 points · first shared 2012 · discussion on HN
- 6Top algorithms preprints of 20101 people · 44 points · first shared 2011 · 2 comments on HN
- 7Elementary Graph Theory and Networks: The one-way street theorem1 people · 36 points · first shared 2011 · 2 comments on HN
- 8Fast Go game recognition1 people · 2 points · first shared 2012 · discussion on HN
- 9A glimpse of the four-dimensional bitruncated 120-cell, with magnets1 people · 2 points · first shared 2013 · discussion on HN
- 10Chaotic evaluation of Sudoku difficulty1 people · 1 points · first shared 2012 · discussion on HN
- 11Binary numbers without the zeros1 people · 1 points · first shared 2012 · discussion on HN
- 12The sad case of Ike Antkare1 people · 1 points · first shared 2011 · discussion on HN
- 13Why Wikipedia's Math Formulas Are So Ugly1 people · 1 points · first shared 2015 · discussion on HN
- 14Chessboards and colorings1 people · 1 points · first shared 2011 · discussion on HN
- 151282491 people · first shared 2010
What HN people wrote when they linked it
bradleyjg · 2016-08-05
Whenever considering a bloom filter also look at cuckoo filters. There are pros and cons of each approach.
See https://bdupras.github.io/filter-tutorial/ and http://11011110.livejournal.com/327681.html as well as the corresponding HN discussions https://news.ycombinator.com/item?id=12124722 and https://news.ycombinator.com/item?id=11795779
amitp · 2014-04-15
Another way of looking at it: A* is Dijkstra where the edge weights have been modified. http://11011110.livejournal.com/135302.html
crux_ · 2011-03-26
That strikes me as extremely unlikely.
I think the complexity class of Sudoko is NP-Complete (a quick google confirms it's not exactly NP but very close: http://11011110.livejournal.com/23221.html?thread=19381 -- complexity is the same as solving SAT problems which have only one unique solution)
slackenerny · 2010-06-01
Cool, this.
A very nifty (if somewhat detailed) complexity analysis of the Algorithm X appeared in blogosphere's festschrift for Knuth's 70, http://11011110.livejournal.com/128249.html
I've used P159 in my absolutely first assignment in the intro programming class. I was to make a N-queens solver. The assignment obviously asked for a 8-line backtracking program. But I was naïve. I went to the library and turned it inside out. My solution was ca. 500 lines, and also implemented a way to find the number of solutions without computing them (this was from IIRC a paper by Rivin), and had a randomized mode which would find just a single solution but for fast for very large N (this I found in Norvig's AIMA in a footnote referencing a paper by J.M., I don't remember the page or the full name)). Good times.
dxjones · 2009-05-27
"When one says Sudoku is NP-complete, one should keep in mind that this refers only to an unusual type of Sudoku puzzle in which there might be multiple solutions."
http://11011110.livejournal.com/23221.html