{"id":981,"date":"2015-01-20T06:00:58","date_gmt":"2015-01-20T04:00:58","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=981"},"modified":"2015-11-30T19:28:02","modified_gmt":"2015-11-30T17:28:02","slug":"listas-con-suma-dada","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/listas-con-suma-dada\/","title":{"rendered":"Listas con suma dada"},"content":{"rendered":"<p>Definir la funci\u00f3n<\/p>\n<pre lang=\"text\">\n   conSuma :: (Eq a, Num a) => [a] -> [[a]] -> [[[a]]]\n<\/pre>\n<p>tal que (conSuma xs yss) es la lista de los vectores de xss cuya suma vectorial es xs. Por ejemplo,<\/p>\n<pre lang=\"text\">\n   ghci> conSuma [9,10,12] [[4,7,3],[3,1,4],[5,3,9],[2,2,5]] \n   [[[4,7,3],[5,3,9]],[[4,7,3],[3,1,4],[2,2,5]]]\n   ghci> conSuma [9,11,12] [[4,7,3],[3,1,4],[5,3,9],[2,2,5]] \n   []\n<\/pre>\n<h4>Soluciones<\/h4>\n<pre lang=\"haskell\">\nimport Data.List (subsequences, transpose)\n\nconSuma :: (Eq a, Num a) => [a] -> [[a]] -> [[[a]]]\nconSuma xs yss = [zss | zss <- subsequences yss, suma zss == xs]\n\n-- (suma xss) es la suma de las listas xs. Por ejemplo,\n--    suma [[4,7,3],[3,1,4],[2,2,5]]  ==  [9,10,12]\nsuma :: Num a => [[a]] -> [a]\nsuma = map sum . transpose \n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Definir la funci\u00f3n conSuma :: (Eq a, Num a) => [a] -> [[a]] -> [[[a]]] tal que (conSuma xs yss) es la lista de los vectores de xss cuya suma vectorial es xs. Por ejemplo, ghci> conSuma [9,10,12] [[4,7,3],[3,1,4],[5,3,9],[2,2,5]] [[[4,7,3],[5,3,9]],[[4,7,3],[3,1,4],[2,2,5]]] ghci> conSuma [9,11,12] [[4,7,3],[3,1,4],[5,3,9],[2,2,5]] [] Soluciones import Data.List (subsequences, transpose) conSuma :: (Eq a, Num&#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":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/981"}],"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=981"}],"version-history":[{"count":3,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/981\/revisions"}],"predecessor-version":[{"id":1801,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/981\/revisions\/1801"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=981"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=981"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=981"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}