Talk:Hopcroft–Karp algorithm/Archive 1

Untitled
This needs an explanation of the "run really fast" step (http://www.fysh.org/~katie/computing/methodologies.txt)
 * I don't understand the comment. --a3nm (talk) 10:48, 4 April 2020 (UTC)

Delta
Is $$N\Delta P$$ the only standard terminology we can use? I would prefer to leave $$\Delta$$ to the maximum degree of the graph. Adking80 (talk) 22:06, 18 July 2008 (UTC)
 * I have seen $$N \oplus P$$ (symmetric difference) used in several papers. It seems a much better notation to me. Also, the meaning of $$\Delta$$ is not explained on the page. I have updated the page accordingly. —Preceding unsigned comment added by Michael Veksler (talk • contribs) 22:29, 9 October 2008 (UTC)

Shortestest
Is shortestest a word? ;D User:Ozzie (talk) 20:37, 7 March 2008 (UTC)
 * Seems outdated. --a3nm (talk) 10:48, 4 April 2020 (UTC)

Maximum vs. maximal
Changed the incorrect "maximum" to "maximal". —Preceding unsigned comment added by 80.145.225.62 (talk • contribs) 22:44, 3 October 2006 UTC


 * I agree. Thanks for persisting after the incorrect revert. —David Eppstein 05:55, 4 October 2006 (UTC)


 * I am sorry for the incorrect revert. I now think that I was wrong. I started this article because the algorithm was mentioned in the text of another article. The only reference I had was CLRS, where it said maximum. So when I saw this edit from an unregistered user, I checked in CLRS, saw that it said maximum, and assumed that the editor was either in error or mischevious. Sorry about this. Let me check that we agree with terminology:


 * If we go through a one-dimmensional state-space (x-axis below), where each state has a value (y-axis below),

B                                                                              /\ A     /  \ /\   /    \                                                                   /  \  /      \                                                                 /    \/        \                                                               /                \


 * then here both A and B are maximal points, while only B is a maximum. This is the terminology used in the article Matching.


 * The description in CLRS is actually just given as an exercise. I tried to solve it, but could not see how to find "maximum set of vertex-disjoint shortest augmenting paths" in $$O(V + E)$$, so I just wrote the pseudocode for the algorithm as described, and put it in my ever-growing TODO to figure out the missing part. I now found a description of the pseudo-code which still says maximum in the comments, but the code clearly gives only something maximal. So the problem was simpler than I thought :) Thanks for the correction, and sorry about my error. Klem fra Nils Grimsmo 09:16, 4 October 2006 (UTC)

Difference from Dinic algorithm (Dinits' algorithm)?
What's the difference between this algorithm and Dinic algorithm? To me, it just looks like Dinic algorithm - only run on a specific input, so it has better time complexity than general-case Dinic. --Lukas Mach 22:27, 27 December 2006 (UTC)


 * It's none... H-K is 1973 algorithm and Dinic is 1976 algorithm. --Lukas Mach 01:55, 26 February 2007 (UTC)


 * Added mention of Dinic's algorithm on the page. --a3nm (talk) 10:48, 4 April 2020 (UTC)

Another estimations
Another estimations are O((V+E)V 1/2) and O(V 5/2): Lipski W., Kombinatoryka dla Programistow, [Combinatorics for Programmers], Wydawnictwa Naukowo-Techniczne, Warzawa, 1982.--Tim32 (talk) 10:58, 19 November 2007 (UTC)


 * Both bounds are worse. We can assume that every vertex is incident to at least one edge, so $$V+E = O(E)$$.  We also know that $$E <  V^2/2$$. Adking80 (talk) 22:04, 18 July 2008 (UTC)