# Shootout/Binary trees

(Difference between revisions)

## 1 Proposals

Port the Clean entry.

## 2 Current

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

```{-# 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```

## 3 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```