# Shootout/Binary trees

## Proposals

Port the Clean entry.

## Proposed entry

Ported to ghc 6.6

```{-# OPTIONS -fbang-patterns #-}

--
-- The Great Computer Language Shootout
-- http://shootout.alioth.debian.org/
--
-- Simon Marlow
-- Rewritten by Don Stewart
--

import System
import Data.Bits
import Text.Printf

data Tree = Nil | Node !Int Tree Tree

minDepth = 4

io s n t = printf "%s of depth %d\t check: %d\n" s n t

main = do
maxDepth <- getArgs >>= return . max (minDepth+2) . read . head :: IO Int

let stretch = make 0 (maxDepth+1)
io "stretch tree" (maxDepth+1) (check stretch)

let long    = make 0 maxDepth

let vs = depth minDepth maxDepth
mapM_ (\(P m d i) -> io (show m ++ "\t trees") d i) vs

io "long lived tree" maxDepth (check long)

data P = P !Int !Int !Int

depth :: Int -> Int -> [P]
depth !d !m
| d > m     = []
| otherwise = P (2*n) d (sumT n d 0) : depth (d+2) m
where
n = 1 `shiftL` (m - d + minDepth)

sumT :: Int -> Int -> Int -> Int
sumT !0 !d !t = t
sumT i d t    = sumT (i-1) d (t + a + b)
where a = check (make i    d)
b = check (make (-i) d)

make :: Int -> Int -> Tree
make !i !0 = Node i Nil Nil
make  i  d = Node i (make (i2-1) d2) (make i2 d2)
where
i2 = 2*i
d2 = d-1

check :: Tree -> Int
check Nil          = 0
check (Node i l r) = i + check l - check r
```

## Old entry

Shortest entry in any language, and almost twice as fast as old entry on my box.

Was speculatively disqualified.

```{-# OPTIONS_GHC -fglasgow-exts -O2 -optc-O3 -funbox-strict-fields #-}
-- The Great Computer Language Shootout
-- http://shootout.alioth.debian.org/
-- Simon Marlow
-- Shortened by Don Stewart

import System; import Text.Printf; import Monad

data Tree = Nil | Node !Int Tree Tree

min' = 4 :: Int

main = do max' <- getArgs >>= return . max (min'+2) . read . head
printf "stretch tree of depth %d\t check: %d\n" (max'+1) (itemCheck \$ make 0 (max'+1))
depthLoop min' max'
printf "long lived tree of depth %d\t check: %d\n" max' (itemCheck \$ make 0 max')

depthLoop d m = when (d <= m) \$ do
printf "%d\t trees of depth %d\t check: %d\n" (2*n) d (sumLoop n d 0)
depthLoop (d+2) m
where n = 2^(m - d + min')

sumLoop 0 d acc = acc
sumLoop k d acc = c `seq` sumLoop (k-1) d (acc + c + c')
where (c,c')  = (itemCheck (make k d), itemCheck (make (-1*k) d))

make i (0::Int) = i `seq` Nil
make i  d       = Node i (make ((2*i)-1) (d-1)) (make (2*i) (d-1))

itemCheck Nil = 0
itemCheck (Node x l r) = x + itemCheck l - itemCheck r
```

## Old Entry

```{-# OPTIONS -O3 -optc-O3 #-}
-- The Great Computer Language Shootout
-- http://shootout.alioth.debian.org/
-- contributed by Einar Karttunen

import System

data Tree = Node  Int Tree Tree | Nil

main = do [n] <- getArgs
let max' = max (min'+2) (read n)
showItemCheck (max'+1) (make 0 (max'+1)) "stretch tree of depth "
let longlived = make 0 max'
depthLoop min' max'
showItemCheck max' longlived "long lived tree of depth "

min' :: Int
min' = 4

showItemCheck d a s = putStrLn (s++show d++"\t check: "++show (itemCheck a))

showCheck i d check = putStrLn (show (2*i)++"\t trees of depth "++show d++"\t check: "++show check)

depthLoop d m | d > m = return ()
depthLoop d m         = showCheck n d (sumLoop n d 0) >> depthLoop (d+2) m
where n = 2^(m - d + min')

sumLoop :: Int -> Int -> Int -> Int
sumLoop 0 d acc = acc
sumLoop k d acc = c `seq` sumLoop (k-1) d (acc + c + c')
where c  = itemCheck (make k d)
c' = itemCheck (make (-1*k) d)

make :: Int -> Int -> Tree
make i 0 = Nil
make i d = Node i (make ((2*i)-1) (d-1)) (make (2*i) (d-1))

itemCheck Nil = 0
itemCheck (Node x l r) = x + itemCheck l - itemCheck r
```