{"id":779,"date":"2014-12-08T06:00:18","date_gmt":"2014-12-08T04:00:18","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=779"},"modified":"2014-12-27T20:53:33","modified_gmt":"2014-12-27T18:53:33","slug":"busqueda-en-lista-de-listas-de-pares","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/busqueda-en-lista-de-listas-de-pares\/","title":{"rendered":"B\u00fasqueda en lista de listas de pares"},"content":{"rendered":"<h4>Enunciado<\/h4>\n<pre lang=\"text\">\n-- Definir la funci\u00f3n\n--    busca :: Eq a => a -> [[(a,b)]] -> [b]\n-- tal que (busca x pss) es la lista de los segundos componentes de los\n-- pares de la lista de listas de pares pss cuya primera componentes es\n-- x. Por ejemplo,\n--    busca 3 [[(3,4)],[(5,4),(3,2),(3,5)],[(4,1),(7,3)]] == [4,2,5]\n<\/pre>\n<h4>Soluciones<\/h4>\n<pre lang=\"haskell\">\n-- 1\u00aa soluci\u00f3n:\nbusca :: Eq a => a -> [[(a,b)]] -> [b]\nbusca x pss = [y | ps <- pss, (z,y) <- ps, z == x]  \n\n-- 2\u00aa soluci\u00f3n:\nbusca2 :: Eq a => a -> [[(a,b)]] -> [b]\nbusca2 x pss = [y | (z,y) <- concat pss, z == x]  \n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Enunciado &#8212; Definir la funci\u00f3n &#8212; busca :: Eq a => a -> [[(a,b)]] -> [b] &#8212; tal que (busca x pss) es la lista de los segundos componentes de los &#8212; pares de la lista de listas de pares pss cuya primera componentes es &#8212; x. Por ejemplo, &#8212; busca 3 [[(3,4)],[(5,4),(3,2),(3,5)],[(4,1),(7,3)]] == [4,2,5]&#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":[8,12],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/779"}],"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=779"}],"version-history":[{"count":5,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/779\/revisions"}],"predecessor-version":[{"id":874,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/779\/revisions\/874"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=779"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=779"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=779"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}