{"id":5586,"date":"2020-02-20T05:30:16","date_gmt":"2020-02-20T03:30:16","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=5586"},"modified":"2020-02-28T07:52:45","modified_gmt":"2020-02-28T05:52:45","slug":"parejas-de-un-conjunto","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/parejas-de-un-conjunto\/","title":{"rendered":"Parejas de un conjunto"},"content":{"rendered":"<p>Definir la funci\u00f3n<\/p>\n<pre lang=\"text\">\n   parejas :: [a] -> [(a,a)]\n<\/pre>\n<p>tal que (parejas xs) es la lista de las parejas formados por los elementos de xs y sus siguientes en xs. Por ejemplo,<\/p>\n<pre lang=\"text\">\n   parejas [1..4] == [(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)]\n   length (parejas [sin,cos,tan,log])  ==  6\n<\/pre>\n<h4>Soluciones<\/h4>\n<pre lang=\"haskell\">\nimport Data.List (tails)\n\n-- 1\u00aa soluci\u00f3n\nparejas :: [a] -> [(a,a)]\nparejas []     = []\nparejas (x:xs) = [(x,y) | y <- xs] ++ parejas xs\n\n-- 2\u00aa soluci\u00f3n\nparejas2 :: [a] -> [(a,a)]\nparejas2 xs =\n  [(x,y) | (x:ys) <- tails xs\n         , y <- ys]\n<\/pre>\n<h4>Otras soluciones<\/h4>\n<ul>\n<li>Se pueden escribir otras soluciones en los comentarios.\n<li>El c\u00f3digo se debe escribir entre una l\u00ednea con &#60;pre lang=\"haskell\"&#62; y otra con &#60;\/pre&#62;\n<\/ul>\n<h4>Pensamiento<\/h4>\n<blockquote><p>\n\"La primera regla del descubrimiento es tener inteligencia y buena suerte. La segunda regla del descubrimiento es sentarse y esperar hasta que se tenga una idea brillante.\" <\/p>\n<p><a href=\"https:\/\/en.wikipedia.org\/wiki\/George_P%C3%B3lya\">George P\u00f3lya<\/a>.\n<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"<p>Definir la funci\u00f3n parejas :: [a] -> [(a,a)] tal que (parejas xs) es la lista de las parejas formados por los elementos de xs y sus siguientes en xs. Por ejemplo, parejas [1..4] == [(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)] length (parejas [sin,cos,tan,log]) == 6 Soluciones import Data.List (tails) &#8212; 1\u00aa soluci\u00f3n parejas :: [a] -> [(a,a)] parejas [] =&#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":[8,75],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/5586"}],"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=5586"}],"version-history":[{"count":5,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/5586\/revisions"}],"predecessor-version":[{"id":5637,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/5586\/revisions\/5637"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=5586"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=5586"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=5586"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}