| <?xml version="1.0" encoding="UTF-8"?> |
| <!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd"> |
| <pkgmetadata> |
| <herd>haskell</herd> |
| <longdescription> |
| Provides a function lcs that takes two lists and returns a longest |
| common sublist. For example, lcs "abcd" "acbd" is either "abd" or |
| "acd". |
| |
| The package provides a simple, stupid and (most of all) slow |
| implementation that needs, for inputs of length m and n, O(m+n) |
| space and O((m+n)!) time in the worst case. |
| |
| It also provides an implementation of the Hunt-Szymanski LCS |
| algorithm, based on that in "String searching algorithms" by |
| Graham A Stephen, ISBN 981021829X. |
| |
| Given inputs xs and ys of length m and n respectively, where there |
| are r pairs (x, y) where x is in xs, y is in ys and x == y, |
| Hunt-Szymanski needs O(r+m+n) space and O((r+m+n)*log(m+n)) time. |
| Thus this is O((m+n)^2) space and O((m+n)^2*log(m+n)) time in the |
| worst case. |
| </longdescription> |
| </pkgmetadata> |
