{"id":1059,"date":"2015-02-10T06:00:29","date_gmt":"2015-02-10T04:00:29","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=1059"},"modified":"2016-05-01T20:19:06","modified_gmt":"2016-05-01T18:19:06","slug":"segmentos-de-longitud-dada","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/segmentos-de-longitud-dada\/","title":{"rendered":"Segmentos de longitud dada"},"content":{"rendered":"<p>Definir la funci\u00f3n<\/p>\n<pre lang=\"text\">\n   segmentos :: Int -> [a] -> [[a]]\n<\/pre>\n<p>tal que (segmentos n xs) es la lista de los segmentos de longitud n de la lista xs. Por ejemplo,<\/p>\n<pre lang=\"text\">\n   segmentos 3 [1..5]  ==  [[1,2,3],[2,3,4],[3,4,5]]\n<\/pre>\n<h4>Soluciones<\/h4>\n<pre lang=\"haskell\">\nimport Data.List (tails)\n\n-- 1\u00aa definici\u00f3n (por recursi\u00f3n)\nsegmentos1 :: Int -> [a] -> [[a]]\nsegmentos1 n xs \n    | length xs < n = []\n    | otherwise     = take n xs : segmentos1 n (tail xs)\n                  \n-- 2\u00aa definici\u00f3n (con tails):\nsegmentos2 :: Int -> [a] -> [[a]]\nsegmentos2 n xs = \n    takeWhile (\\ys -> length ys == n) (map (take n) (tails xs))\n\n-- 3\u00aa definici\u00f3n:\nsegmentos3 :: Int -> [a] -> [[a]]\nsegmentos3 n xs = \n    take (length xs - n + 1) (map (take n) (tails xs))\n\n--    ghci> length (segmentos1 3 [1..30000])\n--    29998\n--    (2.99 secs, 13998816 bytes)\n--    \n--    ghci> length (segmentos2 3 [1..30000])\n--    29998\n--    (0.05 secs, 16941304 bytes)\n--    \n--    ghci> length (segmentos3 3 [1..30000])\n--    29998\n--    (0.04 secs, 10375520 bytes)\n--    \n--    ghci> length (segmentos2 3 [1..1000000])\n--    999998\n--    (0.70 secs, 498098336 bytes)\n--    \n--    ghci> length (segmentos3 3 [1..1000000])\n--    999998\n--    (0.24 secs, 273979304 bytes)\n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Definir la funci\u00f3n segmentos :: Int -> [a] -> [[a]] tal que (segmentos n xs) es la lista de los segmentos de longitud n de la lista xs. Por ejemplo, segmentos 3 [1..5] == [[1,2,3],[2,3,4],[3,4,5]] Soluciones import Data.List (tails) &#8212; 1\u00aa definici\u00f3n (por recursi\u00f3n) segmentos1 :: Int -> [a] -> [[a]] segmentos1 n xs |&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"footnotes":"","_jetpack_memberships_contains_paid_content":false},"categories":[5],"tags":[28,10,11,6,45,47,34],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/1059"}],"collection":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/comments?post=1059"}],"version-history":[{"count":3,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/1059\/revisions"}],"predecessor-version":[{"id":1096,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/1059\/revisions\/1096"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=1059"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=1059"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=1059"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}