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Ring

Chain of class inclusions

Rings ⊃ Commutative rings ⊃ ID ⊃ UFD ⊃ PID ⊃ ED ⊃ Field

Prime

if a | bc then a | b or a | c, i.e. a can't be torn apart if a is prime

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import Control.Monad    (forM_)
import Control.Monad.ST (runST)
import Data.IORef 
import Data.STRef

-- dirty, can't get rid of IO
sumIO :: [Int] -> IO Int
sumIO xs = do
    acc <- newIORef 0
    forM_ xs (modifyIORef acc . (+))

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maximum :: Ord a => [a] -> a
maximum = foldr max (-∞)

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module BatBunker where

import Data.List (findIndices, delete, (\\))
import Data.Ratio 

data Cell = Empty | Wall | Bat | AlphaBat deriving (Show, Eq)
type Map = [[Cell]]
type Coord = (Int, Int)
type Vertex = (Cell, Coord)

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# confidence from 0% to 100%

cat data/1m | time ./dist/build/homework2-hs/homework2-hs 0.0010 0 100 +RTS -K2000m -H500m -RTS
        4.48 real         3.85 user         0.34 sys
cat data/1m | time ./dist/build/homework2-hs/homework2-hs 0.0010 0.1 100 +RTS -K2000m -H500m -RTS
        3.96 real         3.59 user         0.32 sys
cat data/1m | time ./dist/build/homework2-hs/homework2-hs 0.0010 0.2 100 +RTS -K2000m -H500m -RTS
        3.92 real         3.57 user         0.31 sys
cat data/1m | time ./dist/build/homework2-hs/homework2-hs 0.0010 0.3 100 +RTS -K2000m -H500m -RTS
        3.97 real         3.60 user         0.33 sys

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批踢踢實業坊›看板 Gossiping
作者Machinator (\⊙▽⊙/)
看板Gossiping
標題[爆卦] 從近期的抗爭談些社會意識的錯誤
時間Mon Apr 14 22:09:04 2014

錯誤一：「警察是無辜的，要找就找後面下令的人。」

複製貼上故事：

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test 測試 \n\r <123> 

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module Catamorphism where

import Prelude hiding (sum)

data Mu f = InF { outF :: f (Mu f) }

catamorphism :: Functor f => (f a -> a) ->  Mu f -> a
catamorphism f = f . fmap (catamorphism f) . outF

--------------------------------------------------

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Group

• Closed
• Associative
• Identity
• Inverse

Subgroup

Definition

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{-# LANGUAGE OverloadedStrings #-}
import Web.Scotty
import Network.Wai (requestHeaders, pathInfo)
import Data.Text (intercalate, unpack)
import Data.Text.Encoding (decodeUtf8)
import Data.Text.Lazy (fromStrict)
import Network.Mime (defaultMimeLookup)
import Control.Applicative ((<$>))
import Control.Monad.Trans (liftIO)