{"id":4605,"date":"2019-01-21T06:00:22","date_gmt":"2019-01-21T04:00:22","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=4605"},"modified":"2021-04-25T16:23:55","modified_gmt":"2021-04-25T14:23:55","slug":"interseccion-de-listas-infinitas-crecientes-2019a","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/interseccion-de-listas-infinitas-crecientes-2019a\/","title":{"rendered":"Intersecci\u00f3n de listas infinitas crecientes"},"content":{"rendered":"<p>Definir la funci\u00f3n<\/p>\n<pre lang=\"text\"> \n   interseccion :: Ord a => [[a]] -> [a]\n<\/pre>\n<p>tal que (interseccion xss) es la intersecci\u00f3n de la lista no vac\u00eda de listas infinitas crecientes xss; es decir, la lista de los elementos que pertenecen a todas las listas de xss. Por ejemplo,<\/p>\n<pre lang=\"text\"> \n   \u03bb> take 10 (interseccion [[2,4..],[3,6..],[5,10..]])\n   [30,60,90,120,150,180,210,240,270,300]\n   \u03bb> take 10 (interseccion [[2,5..],[3,5..],[5,7..]])\n   [5,11,17,23,29,35,41,47,53,59]\n<\/pre>\n<h4>Soluciones<\/h4>\n<pre lang=\"haskell\">\n-- 1\u00aa soluci\u00f3n\n-- ===========\n\ninterseccion :: Ord a => [[a]] -> [a]\ninterseccion [xs]        = xs\ninterseccion (xs:ys:zss) = interseccionDos xs (interseccion (ys:zss))\n\ninterseccionDos :: Ord a => [a] -> [a] -> [a]\ninterseccionDos (x:xs) (y:ys)\n  | x == y    = x : interseccionDos xs ys\n  | x < y     = interseccionDos (dropWhile (<y) xs) (y:ys)\n  | otherwise = interseccionDos (x:xs) (dropWhile (<x) ys)  \n\n-- 2\u00aa soluci\u00f3n\n-- ===========\n\ninterseccion2 :: Ord a => [[a]] -> [a]\ninterseccion2 = foldl1 interseccionDos\n<\/pre>\n<h4>Pensamiento<\/h4>\n<blockquote><p>\nAlguna vez he pensado<br \/>\nsi el alma ser\u00e1 la ausencia,<br \/>\nmientras m\u00e1s cerca m\u00e1s lejos;<br \/>\nmientras m\u00e1s lejos m\u00e1s cerca.<\/p>\n<p>Antonio Machado\n<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"<p>Definir la funci\u00f3n interseccion :: Ord a => [[a]] -> [a] tal que (interseccion xss) es la intersecci\u00f3n de la lista no vac\u00eda de listas infinitas crecientes xss; es decir, la lista de los elementos que pertenecen a todas las listas de xss. Por ejemplo, \u03bb> take 10 (interseccion [[2,4..],[3,6..],[5,10..]]) [30,60,90,120,150,180,210,240,270,300] \u03bb> take 10 (interseccion&#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":[4],"tags":[59,359,415,11,6],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/4605"}],"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=4605"}],"version-history":[{"count":6,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/4605\/revisions"}],"predecessor-version":[{"id":4650,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/4605\/revisions\/4650"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=4605"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=4605"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=4605"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}