{"id":6735,"date":"2022-03-09T06:00:06","date_gmt":"2022-03-09T04:00:06","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=6735"},"modified":"2022-03-16T13:48:23","modified_gmt":"2022-03-16T11:48:23","slug":"maximos-locales","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/maximos-locales\/","title":{"rendered":"M\u00e1ximos locales"},"content":{"rendered":"<p>Un m\u00e1ximo local de una lista es un elemento de la lista que es mayor que su predecesor y que su sucesor en la lista. Por ejemplo, 5 es un m\u00e1ximo local de [3,2,5,3,7,7,1,6,2] ya que es mayor que 2 (su predecesor) y que 3 (su sucesor).<\/p>\n<p>Definir la funci\u00f3n<\/p>\n<pre lang=\"text\">\n   maximosLocales :: Ord a => [a] -> [a]\n<\/pre>\n<p>tal que (maximosLocales xs) es la lista de los m\u00e1ximos locales de la lista xs. Por ejemplo,<\/p>\n<pre lang=\"text\">\n   maximosLocales [3,2,5,3,7,7,1,6,2]  ==  [5,6]\n   maximosLocales [1..100]             ==  []\n   maximosLocales \"adbpmqexyz\"         ==  \"dpq\"\n<\/pre>\n<h4>Soluciones<\/h4>\n<pre lang=\"haskell\">\nimport Test.QuickCheck\n\n-- 1\u00aa soluci\u00f3n\n-- ===========\n\nmaximosLocales1 :: Ord a => [a] -> [a]\nmaximosLocales1 (x:y:z:xs)\n  | y > x && y > z = y : maximosLocales1 (z:xs)\n  | otherwise      = maximosLocales1 (y:z:xs)\nmaximosLocales1 _ = []\n\n-- 2\u00aa soluci\u00f3n\n-- ===========\n\nmaximosLocales2 :: Ord a => [a] -> [a]\nmaximosLocales2 xs =\n  [y | (x,y,z) <- zip3 xs (tail xs) (drop 2 xs), y > x, y > z]\n\n-- Comprobaci\u00f3n de equivalencia\n-- ============================\n\n-- La propiedad es\nprop_maximosLocales :: [Int] -> Property\nprop_maximosLocales xs =\n  maximosLocales1 xs === maximosLocales2 xs\n\n-- La comprobaci\u00f3n es\n--    \u03bb> quickCheck prop_maximosLocales\n--    +++ OK, passed 100 tests.\n\n-- Comparaci\u00f3n de eficiencia\n-- =========================\n\n-- La comparaci\u00f3n es\n--    \u03bb> last (maximosLocales1 (take (6*10^6) (cycle \"abc\")))\n--    'c'\n--    (3.26 secs, 1,904,464,984 bytes)\n--    \u03bb> last (maximosLocales2 (take (6*10^6) (cycle \"abc\")))\n--    'c'\n--    (2.79 secs, 1,616,465,088 bytes)\n<\/pre>\n<p>El c\u00f3digo se encuentra en <a href=\"https:\/\/github.com\/jaalonso\/Exercitium\/blob\/main\/src\/Maximos_locales.hs\">GitHub<\/a>.<\/p>\n<p>La elaboraci\u00f3n de las soluciones se encuentran en el siguiente v\u00eddeo:<\/p>\n<p><iframe loading=\"lazy\" width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/tPjkXB425Ug\" title=\"YouTube video player\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Un m\u00e1ximo local de una lista es un elemento de la lista que es mayor que su predecesor y que su sucesor en la lista. Por ejemplo, 5 es un m\u00e1ximo local de [3,2,5,3,7,7,1,6,2] ya que es mayor que 2 (su predecesor) y que 3 (su sucesor). Definir la funci\u00f3n maximosLocales :: Ord a =>&#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":[2],"tags":[8,6],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/6735"}],"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=6735"}],"version-history":[{"count":3,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/6735\/revisions"}],"predecessor-version":[{"id":6783,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/6735\/revisions\/6783"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=6735"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=6735"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=6735"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}