1 {- 2 /* $NetBSD: lfu.hs,v 1.1 2006/10/09 12:32:46 yamt Exp $ */ 3 4 /*- 5 * Copyright (c)2005 YAMAMOTO Takashi, 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 -} 30 31 import System.Environment 32 import System.IO 33 import List 34 import Maybe 35 import Monad 36 37 pgmatch idx pg = idx == fst pg 38 39 pglookup :: Eq a => a -> [(a,b)] -> Maybe (a,b) 40 pglookup x = find (pgmatch x) 41 42 pgdequeue :: Eq a => a -> [a] -> [a] 43 pgdequeue = delete 44 45 victim :: Ord b => [(a,b)] -> (a,b) 46 victim = minimumBy p where 47 p x y = compare (snd x) (snd y) 48 49 do_lfu1 npg n q qlen [] = (reverse n, q) 50 do_lfu1 npg n q qlen rs@(r:rs2) = 51 let 52 p = pglookup r q 53 in 54 if isJust p then 55 let 56 opg = fromJust p 57 nq = pgdequeue opg q 58 pg = (fst opg, snd opg + 1) 59 in 60 do_lfu1 npg n (pg:nq) qlen rs2 61 else if qlen < npg then 62 do_lfu1 npg (r:n) ((r,1):q) (qlen+1) rs2 63 else 64 let 65 opg = victim q 66 nq = pgdequeue opg q 67 in 68 do_lfu1 npg (r:n) ((r,1):nq) qlen rs2 69 70 do_lfu npg rs = fst $ do_lfu1 npg [] [] 0 rs 71 72 main = do 73 xs <- getContents 74 args <- getArgs 75 let 76 ls = lines xs 77 npgs::Int 78 npgs = read $ args !! 0 79 pgs::[Int] 80 pgs = map read ls 81 mapM_ print $ do_lfu npgs pgs 82
Indexes created Sat Sep 20 22:09:52 GMT 2025