{"id":7836,"date":"2023-02-06T06:00:14","date_gmt":"2023-02-06T04:00:14","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=7836"},"modified":"2023-01-22T17:31:51","modified_gmt":"2023-01-22T15:31:51","slug":"06-feb-23","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/06-feb-23\/","title":{"rendered":"TAD de las pilas: M\u00e1ximo elemento de una pila"},"content":{"rendered":"

Utilizando el tipo abstracto de datos de las pilas<\/a>, definir la funci\u00f3n<\/p>\n

\n   maxPila :: Ord a => Pila a -> a\n<\/pre>\n
tal que maxPila p<\/code> sea el mayor de los elementos de la pila p<\/code>. Por ejemplo,<\/p>\n
\n   \u03bb> maxPila (apila 3 (apila 5 (apila 1 vacia)))\n   5\n<\/pre>\n
Soluciones<\/b><\/p>\n
A continuaci\u00f3n se muestran las soluciones en Haskell<\/a> y las soluciones en Python<\/a>.<\/p>\n
<\/a>
\nSoluciones en Haskell<\/b><\/p>\n
\nimport TAD.Pila (Pila, vacia, apila, esVacia, cima, desapila)\nimport Transformaciones_pilas_listas (pilaAlista)\nimport Test.QuickCheck\n\n-- 1\u00aa soluci\u00f3n\n-- ===========\n\nmaxPila1 :: Ord a => Pila a -> a\nmaxPila1 p\n  | esVacia dp = cp\n  | otherwise  = max cp (maxPila1 dp)\n  where cp = cima p\n        dp = desapila p\n\n-- 2\u00aa soluci\u00f3n\n-- ===========\n\n-- Se usar\u00e1 la funci\u00f3n pilaAlista del ejercicio\n-- \"Transformaciones entre pilas y listas\" que se encuentra en\n-- https:\/\/bit.ly\/3ZHewQ8\n\nmaxPila2 :: Ord a => Pila a -> a\nmaxPila2 =\n  maximum . pilaAlista\n\n-- Comprobaci\u00f3n de equivalencia\n-- ============================\n\n-- La propiedad es\nprop_maxPila :: Pila Int -> Property\nprop_maxPila p =\n  not (esVacia p) ==> maxPila1 p == maxPila2 p\n\n-- La comprobaci\u00f3n es\n--    \u03bb> quickCheck prop_maxPila\n--    +++ OK, passed 100 tests; 17 discarded.\n<\/pre>\n
<\/a>
\nSoluciones en Python<\/b><\/p>\n
\nfrom copy import deepcopy\nfrom typing import TypeVar\n\nfrom hypothesis import assume, given\n\nfrom src.TAD.pila import (Pila, apila, cima, desapila, esVacia, pilaAleatoria,\n                          vacia)\nfrom src.transformaciones_pilas_listas import pilaAlista\n\nA = TypeVar('A', int, float, str)\n\n# 1\u00aa soluci\u00f3n\n# ===========\n\ndef maxPila1(p: Pila[A]) -> A:\n    cp = cima(p)\n    dp = desapila(p)\n    if esVacia(dp):\n        return cp\n    return max(cp, maxPila1(dp))\n\n# 2\u00aa soluci\u00f3n\n# ===========\n\n# Se usar\u00e1 la funci\u00f3n pilaAlista del ejercicio\n# \"Transformaciones entre pilas y listas\" que se encuentra en\n# https:\/\/bit.ly\/3ZHewQ8\n\ndef maxPila2(p: Pila[A]) -> A:\n    return max(pilaAlista(p))\n\n# 3\u00aa soluci\u00f3n\n# ===========\n\ndef maxPila3Aux(p: Pila[A]) -> A:\n    cp = p.cima()\n    p.desapila()\n    if esVacia(p):\n        return cp\n    return max(cp, maxPila3Aux(p))\n\ndef maxPila3(p: Pila[A]) -> A:\n    q = deepcopy(p)\n    return maxPila3Aux(q)\n\n# 4\u00aa soluci\u00f3n\n# ===========\n\ndef maxPila4Aux(p: Pila[A]) -> A:\n    r = p.cima()\n    while not esVacia(p):\n        cp = p.cima()\n        if cp > r:\n            r = cp\n        p.desapila()\n    return r\n\ndef maxPila4(p: Pila[A]) -> A:\n    q = deepcopy(p)\n    return maxPila4Aux(q)\n\n# Comprobaci\u00f3n de equivalencia de las definiciones\n# ================================================\n\n# La propiedad es\n@given(p=pilaAleatoria())\ndef test_maxPila(p: Pila[int]) -> None:\n    assume(not esVacia(p))\n    r = maxPila1(p)\n    assert maxPila2(p) == r\n    assert maxPila3(p) == r\n    assert maxPila4(p) == r\n\n# La comprobaci\u00f3n es\n#    src> poetry run pytest -q maxPila.py\n#    1 passed in 0.25s\n<\/pre>\n","protected":false},"excerpt":{"rendered":"
Utilizando el tipo abstracto de datos de las pilas, definir la funci\u00f3n maxPila :: Ord a => Pila a -> a tal que maxPila p sea el mayor de los elementos de la pila p. Por ejemplo, \u03bb> maxPila (apila 3 (apila 5 (apila 1 vacia))) 5 Soluciones A continuaci\u00f3n se muestran las soluciones en…<\/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":[581],"tags":[586,357],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/7836"}],"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=7836"}],"version-history":[{"count":3,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/7836\/revisions"}],"predecessor-version":[{"id":7876,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/7836\/revisions\/7876"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=7836"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=7836"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=7836"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}