{"id":2514,"date":"2016-06-02T06:20:23","date_gmt":"2016-06-02T04:20:23","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=2514"},"modified":"2016-06-02T06:23:24","modified_gmt":"2016-06-02T04:23:24","slug":"sucesion-de-sumas-de-digitos","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/sucesion-de-sumas-de-digitos\/","title":{"rendered":"Sucesi\u00f3n de sumas de d\u00edgitos"},"content":{"rendered":"<p>Definir la lista<\/p>\n<pre lang=\"text\">\n   sucSumaDigitos :: [Integer]\n<\/pre>\n<p>cuyos elementos son los t\u00e9rminos de la sucesi\u00f3n a(n) definidos por a(0) = 1 y, para n \u2265 1, a(n) es la suma de los d\u00edgitos de todos los t\u00e9rminos precedentes. Por ejemplo,<\/p>\n<pre lang=\"text\">\n   \u03bb> take 20 sucSumaDigitos\n   [1,1,2,4,8,16,23,28,38,49,62,70,77,91,101,103,107,115,122,127]\n   \u03bb> sucSumaDigitos !! 1000000\n   31054319\n<\/pre>\n<h4>Soluciones<\/h4>\n<p>[schedule expon=&#8217;2016-06-09&#8242; expat=\u00bb06:00&#8243;]<\/p>\n<ul>\n<li>Las soluciones se pueden escribir en los comentarios hasta el 09 de junio.\n<li>El c\u00f3digo se debe escribir entre una l\u00ednea con &#60;pre lang=\u00bbhaskell\u00bb&#62; y otra con &#60;\/pre&#62;\n<\/ul>\n<p>[\/schedule]<\/p>\n<p>[schedule on=&#8217;2016-06-09&#8242; at=\u00bb06:00&#8243;]<\/p>\n<pre lang=\"haskell\">\r\n-- 1\u00aa definici\u00f3n\r\n-- =============\r\n\r\nsucSumaDigitos1:: [Integer]\r\nsucSumaDigitos1 = 1 : iterate f 1\r\n    where f x = x + sum (digitos x)\r\n\r\ndigitos:: Integer -> [Integer]\r\ndigitos n = [read [x] | x <- show n]\r\n\r\n-- 2\u00aa definici\u00f3n\r\n-- =============\r\n\r\nsucSumaDigitos2:: [Integer]\r\nsucSumaDigitos2 = 1 : iterate f 1\r\n    where f x = x + sumaDigitos x\r\n\r\nsumaDigitos n\r\n    | n < 10    = n\r\n    | otherwise = sumaDigitos q + r\r\n    where (q,r) = divMod n 10 \r\n\r\n-- Comparaci\u00f3n de eficiencia\r\n-- =========================\r\n\r\n--    \u03bb> sucSumaDigitos1 !! 1000000\r\n--    31054319\r\n--    (24.04 secs, 52,022,125,016 bytes)\r\n--    \u03bb> sucSumaDigitos2 !! 1000000\r\n--    31054319\r\n--    (10.86 secs, 5,267,144,472 bytes)\r\n<\/pre>\n<p>[\/schedule]<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Definir la lista sucSumaDigitos :: [Integer] cuyos elementos son los t\u00e9rminos de la sucesi\u00f3n a(n) definidos por a(0) = 1 y, para n \u2265 1, a(n) es la suma de los d\u00edgitos de todos los t\u00e9rminos precedentes. Por ejemplo, \u03bb> take 20 sucSumaDigitos [1,1,2,4,8,16,23,28,38,49,62,70,77,91,101,103,107,115,122,127] \u03bb> sucSumaDigitos !! 1000000 31054319 Soluciones [schedule expon=&#8217;2016-06-09&#8242; expat=\u00bb06:00&#8243;] Las soluciones&#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":[2],"tags":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/2514"}],"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=2514"}],"version-history":[{"count":2,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/2514\/revisions"}],"predecessor-version":[{"id":2516,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/2514\/revisions\/2516"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=2514"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=2514"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=2514"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}