diff options
Diffstat (limited to 'dev-haskell/lcs/metadata.xml')
| -rw-r--r-- | dev-haskell/lcs/metadata.xml | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/dev-haskell/lcs/metadata.xml b/dev-haskell/lcs/metadata.xml new file mode 100644 index 000000000000..fa121ce23df5 --- /dev/null +++ b/dev-haskell/lcs/metadata.xml @@ -0,0 +1,24 @@ +<?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> |