33 lines
1.1 KiB
Haskell
33 lines
1.1 KiB
Haskell
import Data.Tree (Tree,Forest(..))
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import qualified Data.Tree as Tree
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data BinTree a = Empty
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| Node a (BinTree a) (BinTree a)
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deriving (Eq,Ord,Show)
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-- | Function to transform our internal BinTree type to the
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-- type of Tree declared in Data.Tree (from containers package)
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-- so that the function Tree.drawForest can use
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binTreeToForestString :: (Show a) => BinTree a -> Forest String
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binTreeToForestString Empty = []
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binTreeToForestString (Node x left right) =
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[Tree.Node (show x) ((binTreeToForestString left) ++ (binTreeToForestString right))]
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-- | Function that given a BinTree print a representation of it in the console
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prettyPrintTree :: (Show a) => BinTree a -> IO ()
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prettyPrintTree = putStrLn . Tree.drawForest . binTreeToForestString
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nullTree = Node 0 nullTree nullTree
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-- take all element of a BinTree
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-- up to some depth
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treeTakeDepth _ Empty = Empty
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treeTakeDepth 0 _ = Empty
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treeTakeDepth n (Node x left right) = let
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nl = treeTakeDepth (n-1) left
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nr = treeTakeDepth (n-1) right
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in
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Node x nl nr
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main = prettyPrintTree (treeTakeDepth 4 nullTree)
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