Doubly-linked list/Traversal: Difference between revisions
Content added Content deleted
(→{{header|Haskell}}: shorter name for the loop function, "go" ; add field labels, lastNode etc.) |
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<lang haskell>main = print . traverse True $ create [10,20,30,40] |
<lang haskell>main = print . traverse True $ create [10,20,30,40] |
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data DList a = Leaf | Node (DList a) a (DList a) |
data DList a = Leaf | Node { prev::(DList a), elt::a, next::(DList a) } |
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create = |
create = go Leaf |
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where |
where go _ [] = Leaf |
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go prev (x:xs) = current |
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where current = Node prev x next |
where current = Node prev x next |
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next = |
next = go current xs |
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isLeaf Leaf = True |
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isLeaf _ = False |
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lastNode Leaf = Leaf |
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lastNode dl = until (isLeaf.next) next dl |
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traverse _ Leaf = [] |
traverse _ Leaf = [] |
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