{"id":2898,"date":"2017-02-07T06:00:25","date_gmt":"2017-02-07T04:00:25","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=2898"},"modified":"2017-02-14T07:10:47","modified_gmt":"2017-02-14T05:10:47","slug":"prefijo-con-suma-acotada","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/prefijo-con-suma-acotada\/","title":{"rendered":"Prefijo con suma acotada"},"content":{"rendered":"<p>Definir la funci\u00f3n<\/p>\n<pre lang=\"text\">\n   prefijoAcotado :: (Num a, Ord a) => a -> [a] -> [a]\n<\/pre>\n<p>tal que (prefijoAcotado x ys) es el mayor prefijo de ys cuya suma es menor que x. Por ejemplo,<\/p>\n<pre lang=\"text\">\n   prefijoAcotado 10 [3,2,5,7]  ==  [3,2]\n   prefijoAcotado 10 [1..]      ==  [1,2,3]\n<\/pre>\n<h4>Soluciones<\/h4>\n<pre lang=\"haskell\">\n-- 1\u00aa definici\u00f3n (por recursi\u00f3n):\nprefijoAcotado :: (Num a, Ord a) => a -> [a] -> [a]\nprefijoAcotado x [] = []\nprefijoAcotado x (y:ys)\n  | y < x     = y : prefijoAcotado (x-y) ys\n  | otherwise = []\n\n-- 2\u00aa definici\u00f3n (con scanl1 y takeWhile):\nprefijoAcotado2 :: (Num a, Ord a) => a -> [a] -> [a]\nprefijoAcotado2 x ys = map fst conSumasAcotadas\n  where \n    sumas            = scanl1 (+) ys \n    conSumas         = zip ys sumas\n    conSumasAcotadas = takeWhile (\\(a,b) -> b < x) conSumas\n\n-- 3\u00aa definici\u00f3n (con (.)):\nprefijoAcotado3 :: (Num a, Ord a) => a -> [a] -> [a]\nprefijoAcotado3 x ys = map fst conSumasAcotadas\n  where \n    sumas            = scanl1 (+) ys \n    conSumas         = zip ys sumas\n    conSumasAcotadas = takeWhile ((<x) . snd) conSumas\n\n-- 4\u00aa definici\u00f3n:\nprefijoAcotado4 :: (Num a, Ord a) => a -> [a] -> [a]\nprefijoAcotado4 x ys = \n    map fst (takeWhile ((<x) . snd) (zip ys (scanl1 (+) ys)))\n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Definir la funci\u00f3n prefijoAcotado :: (Num a, Ord a) => a -> [a] -> [a] tal que (prefijoAcotado x ys) es el mayor prefijo de ys cuya suma es menor que x. Por ejemplo, prefijoAcotado 10 [3,2,5,7] == [3,2] prefijoAcotado 10 [1..] == [1,2,3] Soluciones &#8212; 1\u00aa definici\u00f3n (por recursi\u00f3n): prefijoAcotado :: (Num a, Ord&#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":[80,10,11,6,252,16,34,9],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/2898"}],"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=2898"}],"version-history":[{"count":3,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/2898\/revisions"}],"predecessor-version":[{"id":2951,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/2898\/revisions\/2951"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=2898"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=2898"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=2898"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}