mirror of
https://github.com/AdrianKuta/Tree-Data-Structure.git
synced 2026-06-20 03:10:14 +02:00
Adrian Kuta
c45c5b7afa
Core additive work for v3.4 (non-breaking): - Rewrite nodeCount(), height(), clear() and the post-order iterator iteratively so deep/degenerate trees no longer throw StackOverflowError (verified to 50k deep). - Add lazy Sequence traversal: asSequence(order), pre/post/levelOrderSequence(). - Add navigation extensions: isLeaf, degree, root(), ancestors(), siblings(), leaves(), descendants(). - Add functional extensions: findNode, filterNodes, anyNode, allNodes, countNodes, foldNodes, mapValues, deepCopy, structurallyEquals (all stack-safe). - Add tests for stack-safety, the new APIs, and previously-uncovered height/depth/nodeCount/path (incl. exception paths). 40 tests green on JVM.
32 lines
1.5 KiB
Kotlin
32 lines
1.5 KiB
Kotlin
package com.github.adriankuta.datastructure.tree
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import com.github.adriankuta.datastructure.tree.iterators.LevelOrderTreeIterator
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import com.github.adriankuta.datastructure.tree.iterators.PostOrderTreeIterator
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import com.github.adriankuta.datastructure.tree.iterators.PreOrderTreeIterator
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import com.github.adriankuta.datastructure.tree.iterators.TreeNodeIterators
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/**
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* Lazily traverses this subtree in the given [order] as a [Sequence], without forcing the whole
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* traversal up front. Pairs with the Kotlin stdlib, e.g.
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* `root.asSequence().map { it.value }.firstOrNull { it == target }`.
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*/
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fun <T> TreeNode<T>.asSequence(
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order: TreeNodeIterators = TreeNodeIterators.PreOrder,
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): Sequence<TreeNode<T>> {
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val self = this
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return when (order) {
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TreeNodeIterators.PreOrder -> Sequence { PreOrderTreeIterator(self) }
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TreeNodeIterators.PostOrder -> Sequence { PostOrderTreeIterator(self) }
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TreeNodeIterators.LevelOrder -> Sequence { LevelOrderTreeIterator(self) }
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}
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}
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/** Lazy pre-order traversal as a [Sequence]. */
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fun <T> TreeNode<T>.preOrderSequence(): Sequence<TreeNode<T>> = asSequence(TreeNodeIterators.PreOrder)
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/** Lazy post-order traversal as a [Sequence]. */
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fun <T> TreeNode<T>.postOrderSequence(): Sequence<TreeNode<T>> = asSequence(TreeNodeIterators.PostOrder)
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/** Lazy level-order (breadth-first) traversal as a [Sequence]. */
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fun <T> TreeNode<T>.levelOrderSequence(): Sequence<TreeNode<T>> = asSequence(TreeNodeIterators.LevelOrder)
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