\nYa algunos pedagogos comienzan a comprender que los ni\u00f1os no deben ser educados como meros aprendices de hombre, que hay algo sagrado en la infancia para vivir plenamente por ella.<\/p>\n
Antonio Machado\n<\/p><\/blockquote>\n
[\/schedule]<\/p>\n
[schedule on=’2019-06-04′ at=\u00bb06:00″]<\/p>\n
\r\nimport Data.List ((\\\\))\r\nimport Data.Tree\r\n\r\n-- Definici\u00f3n de arbolReinas\r\n-- =========================\r\n\r\narbolReinas :: Int -> Tree [Int]\r\narbolReinas n = expansion n []\r\n where\r\n expansion m xs = Node xs [expansion (m-1) ys | ys <- sucesores n xs]\r\n\r\n-- (sucesores n xs) es la lista de los sucesores del estado xs en el\r\n-- problema de las n reinas. Por ejemplo,\r\n-- sucesores 4 [] == [[1],[2],[3],[4]]\r\n-- sucesores 4 [1] == [[3,1],[4,1]]\r\n-- sucesores 4 [4,1] == [[2,4,1]]\r\n-- sucesores 4 [2,4,1] == []\r\nsucesores :: Int -> [Int] -> [[Int]]\r\nsucesores n xs = [y:xs | y <- [1..n] \\\\ xs\r\n , noAtaca y xs 1]\r\n\r\n-- (noAtaca y xs d) se verifica si la reina en la fila y no ataca a las\r\n-- colocadas en las filas xs donde d es el n\u00famero de columnas desde la\r\n-- de la posici\u00f3n de x a la primera de xs.\r\nnoAtaca :: Int -> [Int] -> Int -> Bool\r\nnoAtaca _ [] _ = True\r\nnoAtaca y (x:xs) distH = abs(y-x) \/= distH &&\r\n noAtaca y xs (distH + 1) \r\n\r\n-- Definici\u00f3n de nEstados\r\n-- ======================\r\n\r\nnEstados :: Int -> Int\r\nnEstados = length . arbolReinas\r\n\r\n-- Definici\u00f3n de solucionesReinas\r\n-- ==============================\r\n\r\n-- \u03bb> soluciones 4\r\n-- [[3,1,4,2],[2,4,1,3]]\r\n-- \u03bb> soluciones 5\r\n-- [[4,2,5,3,1],[3,5,2,4,1],[5,3,1,4,2],[4,1,3,5,2],[5,2,4,1,3],\r\n-- [1,4,2,5,3],[2,5,3,1,4],[1,3,5,2,4],[3,1,4,2,5],[2,4,1,3,5]]\r\nsoluciones :: Int -> [[Int]]\r\nsoluciones n =\r\n filter (\\xs -> length xs == n) (estados n)\r\n\r\n-- (estados n) es la lista de estados del problema de las n reinas. Por\r\n-- ejemplo, \r\n-- \u03bb> estados 4\r\n-- [[],\r\n-- [1],[2],[3],[4],\r\n-- [3,1],[4,1],[4,2],[1,3],[1,4],[2,4],\r\n-- [2,4,1],[1,4,2],[4,1,3],[3,1,4],\r\n-- [3,1,4,2],[2,4,1,3]]\r\nestados :: Int -> [[Int]]\r\nestados = concat . levels . arbolReinas\r\n\r\n-- Definici\u00f3n de nSoluciones\r\n-- =========================\r\n\r\nnSoluciones :: Int -> Int\r\nnSoluciones = length . soluciones\r\n<\/pre>\n[\/schedule]<\/p>\n","protected":false},"excerpt":{"rendered":"
El problema de las N reinas consiste en colocar N reinas en tablero rectangular de dimensiones N por N de forma que no se encuentren m\u00e1s de una en la misma l\u00ednea: horizontal, vertical o diagonal. Por ejemplo, una soluci\u00f3n para el problema de las 4 reinas es |—|—|—|—| | | R | | |…<\/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\/5049"}],"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=5049"}],"version-history":[{"count":1,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/5049\/revisions"}],"predecessor-version":[{"id":5050,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/5049\/revisions\/5050"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=5049"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=5049"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=5049"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}