{"id":7812,"date":"2023-01-25T06:00:10","date_gmt":"2023-01-25T04:00:10","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=7812"},"modified":"2023-01-22T17:29:24","modified_gmt":"2023-01-22T15:29:24","slug":"25-ene-23","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/25-ene-23\/","title":{"rendered":"TAD de las pilas: Aplicaci\u00f3n de una funci\u00f3n a los elementos de una pila"},"content":{"rendered":"<p>Utilizando el <a href=\"https:\/\/bit.ly\/3GTToyK\">tipo abstracto de datos de las pilas<\/a>, definir la funci\u00f3n<\/p>\n<pre lang=\"text\">\n   mapPila :: (a -> a) -> Pila a -> Pila a\n<\/pre>\n<p>tal que <code>mapPila f p<\/code> es la pila formada con las im\u00e1genes por <code>f<\/code> de los elementos de pila <code>p<\/code>, en el mismo orden. Por ejemplo,<\/p>\n<pre lang=\"text\">\n   \u03bb> mapPila (+1) (apila 5 (apila 2 (apila 7 vacia)))\n   6 | 3 | 8\n<\/pre>\n<p><b>Soluciones<\/b><\/p>\n<p>A continuaci\u00f3n se muestran las <a href=\"#haskell\">soluciones en Haskell<\/a> y las <a href=\"#python\">soluciones en Python<\/a>.<\/p>\n<p><a name=\"haskell\"><\/a><br \/>\n<b>Soluciones en Haskell<\/b><\/p>\n<pre lang=\"haskell\">\nimport TAD.Pila (Pila, vacia, apila, esVacia, cima, desapila)\nimport Transformaciones_pilas_listas (listaApila, pilaAlista)\nimport Test.QuickCheck.HigherOrder\n\n-- 1\u00aa soluci\u00f3n\n-- ===========\n\nmapPila1 :: (a -> a) -> Pila a -> Pila a\nmapPila1 f p\n  | esVacia p = p\n  | otherwise = apila (f cp) (mapPila1 f dp)\n  where cp = cima p\n        dp = desapila p\n\n-- 2\u00aa soluci\u00f3n\n-- ===========\n\n-- Se usar\u00e1n las funciones listaApila y pilaAlista del ejercicio\n-- \"Transformaciones entre pilas y listas\" que se encuentra en\n-- https:\/\/bit.ly\/3ZHewQ8\n\nmapPila2 :: (a -> a) -> Pila a -> Pila a\nmapPila2 f p =\n  listaApila (map f (pilaAlista p))\n\n-- Comprobaci\u00f3n de equivalencia\n-- ============================\n\n-- La propiedad es\nprop_mapPila :: (Int -> Int) -> [Int] -> Bool\nprop_mapPila f p =\n  mapPila1 f q == mapPila2 f q\n  where q = listaApila p\n\n-- La comprobaci\u00f3n es\n--    \u03bb> quickCheck' prop_mapPila\n--    +++ OK, passed 100 tests.\n<\/pre>\n<p><a name=\"python\"><\/a><br \/>\n<b>Soluciones en Python<\/b><\/p>\n<pre lang=\"python\">\nfrom copy import deepcopy\nfrom typing import Callable, TypeVar\n\nfrom hypothesis import given\n\nfrom src.TAD.pila import (Pila, apila, cima, desapila, esVacia, pilaAleatoria,\n                          vacia)\nfrom src.transformaciones_pilas_listas import listaApila, pilaAlista\n\nA = TypeVar('A')\n\n# 1\u00aa soluci\u00f3n\n# ===========\n\ndef mapPila1(f: Callable[[A], A], p: Pila[A]) -> Pila[A]:\n    if esVacia(p):\n        return p\n    cp = cima(p)\n    dp = desapila(p)\n    return apila(f(cp), mapPila1(f, dp))\n\n# 2\u00aa soluci\u00f3n\n# ===========\n\n# Se usar\u00e1n las funciones listaApila y pilaAlista del ejercicio\n# \"Transformaciones entre pilas y listas\" que se encuentra en\n# https:\/\/bit.ly\/3ZHewQ8\n\ndef mapPila2(f: Callable[[A], A], p: Pila[A]) -> Pila[A]:\n    return listaApila(list(map(f, pilaAlista(p))))\n\n# 3\u00aa soluci\u00f3n\n# ===========\n\ndef mapPila3Aux(f: Callable[[A], A], p: Pila[A]) -> Pila[A]:\n    if p.esVacia():\n        return p\n    cp = p.cima()\n    p.desapila()\n    r = mapPila3Aux(f, p)\n    r.apila(f(cp))\n    return r\n\ndef mapPila3(f: Callable[[A], A], p: Pila[A]) -> Pila[A]:\n    p1 = deepcopy(p)\n    return mapPila3Aux(f, p1)\n\n# 4\u00aa soluci\u00f3n\n# ===========\n\ndef mapPila4Aux(f: Callable[[A], A], p: Pila[A]) -> Pila[A]:\n    r: Pila[A] = Pila()\n    while not p.esVacia():\n        cp = p.cima()\n        p.desapila()\n        r.apila(f(cp))\n    r1: Pila[A] = Pila()\n    while not r.esVacia():\n        r1.apila(r.cima())\n        r.desapila()\n    return r1\n\ndef mapPila4(f: Callable[[A], A], p: Pila[A]) -> Pila[A]:\n    p1 = deepcopy(p)\n    return mapPila4Aux(f, p1)\n\n# Comprobaci\u00f3n de equivalencia de las definiciones\n# ================================================\n\n# La propiedad es\n@given(p=pilaAleatoria())\ndef test_mapPila(p: Pila[int]) -> None:\n    r = mapPila1(lambda x: x + 1 == 0, p)\n    assert mapPila2(lambda x: x + 1 == 0, p) == r\n    assert mapPila3(lambda x: x + 1 == 0, p) == r\n    assert mapPila4(lambda x: x + 1 == 0, p) == r\n\n# La comprobaci\u00f3n es\n#    src> poetry run pytest -q mapPila.py\n#    1 passed in 0.29s\n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Utilizando el tipo abstracto de datos de las pilas, definir la funci\u00f3n mapPila :: (a -> a) -> Pila a -> Pila a tal que mapPila f p es la pila formada con las im\u00e1genes por f de los elementos de pila p, en el mismo orden. Por ejemplo, \u03bb> mapPila (+1) (apila 5 (apila&#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":[581],"tags":[586,585],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/7812"}],"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=7812"}],"version-history":[{"count":5,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/7812\/revisions"}],"predecessor-version":[{"id":7868,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/7812\/revisions\/7868"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=7812"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=7812"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=7812"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}