82 lines
2.3 KiB
Haskell
82 lines
2.3 KiB
Haskell
{-
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/* $NetBSD: lfu.hs,v 1.1 2006/10/09 12:32:46 yamt Exp $ */
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/*-
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* Copyright (c)2005 YAMAMOTO Takashi,
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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-}
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import System.Environment
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import System.IO
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import List
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import Maybe
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import Monad
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pgmatch idx pg = idx == fst pg
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pglookup :: Eq a => a -> [(a,b)] -> Maybe (a,b)
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pglookup x = find (pgmatch x)
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pgdequeue :: Eq a => a -> [a] -> [a]
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pgdequeue = delete
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victim :: Ord b => [(a,b)] -> (a,b)
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victim = minimumBy p where
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p x y = compare (snd x) (snd y)
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do_lfu1 npg n q qlen [] = (reverse n, q)
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do_lfu1 npg n q qlen rs@(r:rs2) =
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let
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p = pglookup r q
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in
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if isJust p then
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let
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opg = fromJust p
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nq = pgdequeue opg q
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pg = (fst opg, snd opg + 1)
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in
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do_lfu1 npg n (pg:nq) qlen rs2
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else if qlen < npg then
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do_lfu1 npg (r:n) ((r,1):q) (qlen+1) rs2
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else
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let
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opg = victim q
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nq = pgdequeue opg q
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in
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do_lfu1 npg (r:n) ((r,1):nq) qlen rs2
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do_lfu npg rs = fst $ do_lfu1 npg [] [] 0 rs
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main = do
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xs <- getContents
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args <- getArgs
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let
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ls = lines xs
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npgs::Int
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npgs = read $ args !! 0
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pgs::[Int]
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pgs = map read ls
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mapM_ print $ do_lfu npgs pgs
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