{"id":2101,"date":"2016-02-11T06:00:32","date_gmt":"2016-02-11T04:00:32","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=2101"},"modified":"2022-03-26T12:12:29","modified_gmt":"2022-03-26T10:12:29","slug":"compactacion-de-listas","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/compactacion-de-listas\/","title":{"rendered":"Compactaci\u00f3n de listas"},"content":{"rendered":"<p>Definir la funci\u00f3n<\/p>\n<pre lang=\"text\">\n   compactada :: [Maybe Int] -> [Int]\n<\/pre>\n<p>tal que (compacta xs) es la lista obtenida al compactar xs con las siguientes reglas:<\/p>\n<ol>\n<li>se eliminan los elementos Nothing;<\/li>\n<li>si dos elementos consecutivos tienen el mismo valor, se sustituyen por el sucesor de su valor y<\/li>\n<li>los restantes elementos no se cambian.<\/li>\n<\/ol>\n<p>Por ejemplo,<\/p>\n<pre lang=\"text\">\n    \u03bb> compactada [Just 1,Nothing,Just 1,Just 4,Just 4,Just 3,Just 6]\n    [2,5,3,6]\n    \u03bb> compactada [Just 1,Nothing,Just 1,Just 1,Just 4,Just 3,Just 6]\n    [2,1,4,3,6]\n    \u03bb> compactada [Just 1,Nothing,Just 1,Just 1,Just 4,Just 4,Just 6]\n    [2,1,5,6]\n    \u03bb> compactada [Just 1,Nothing,Just 1,Just 1,Just 4,Just 3,Just 4]\n    [2,1,4,3,4]\n    \u03bb> compactada [Just 1,Nothing,Just 1,Just 2,Just 4,Just 3,Just 4]\n    [2,2,4,3,4]\n<\/pre>\n<h4>Soluciones<\/h4>\n<pre lang=\"haskell\">\n-- 1\u00aa definici\u00f3n\ncompactada1 :: [Maybe Int] -> [Int]\ncompactada1 xs = aux (valores xs)\n    where aux (x:y:xs) | x == y    = x+1 : aux xs\n                       | otherwise = x : aux (y:xs)\n          aux xs                   = xs\n\n-- (valores vs) es la lista de los valores de vs. Por ejemplo,\n--    ghci> valores [Just 1,Nothing,Just 1,Nothing,Just 3,Just 6]\n--    [1,1,3,6]\nvalores :: [Maybe Int] -> [Int]\nvalores xs = [x | Just x <- xs]\n\n-- 2\u00aa definici\u00f3n de valores (por recursi\u00f3n):\nvalores2 :: [Maybe Int] -> [Int]\nvalores2 []            = []\nvalores2 ((Just v):vs) = v: valores2 vs\nvalores2 (Nothing:vs)  = valores2 vs\n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Definir la funci\u00f3n compactada :: [Maybe Int] -> [Int] tal que (compacta xs) es la lista obtenida al compactar xs con las siguientes reglas: se eliminan los elementos Nothing; si dos elementos consecutivos tienen el mismo valor, se sustituyen por el sucesor de su valor y los restantes elementos no se cambian. Por ejemplo, \u03bb>&#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":[8,500,6],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/2101"}],"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=2101"}],"version-history":[{"count":5,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/2101\/revisions"}],"predecessor-version":[{"id":2137,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/2101\/revisions\/2137"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=2101"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=2101"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=2101"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}