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Commit cc69d51

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Breadth first search tree traversal
1 parent 857afc4 commit cc69d51

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5 files changed

+244
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5 files changed

+244
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package pl.dmichalski.algorithms.data_structures._6_tree_traversal._1_breadth_first_search
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class BinarySearchTree {
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private var root: TreeNode? = null
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fun insert(value: Int): BinarySearchTree {
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val node = TreeNode(value)
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if (root == null) {
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root = node
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return this
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} else {
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var current = this.root
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while (true) {
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if (value < current!!.getValue()) {
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if (current.getLeft() == null) {
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current.setLeft(node)
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return this
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} else {
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current = current.getLeft()
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}
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} else if (value > current.getValue()) {
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if (current.getRight() == null) {
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current.setRight(node)
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return this
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} else {
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current = current.getRight()
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}
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} else {
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return this
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}
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}
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}
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}
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fun breadthFistSearch(): List<Int> {
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if (this.root == null) {
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return mutableListOf()
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}
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val data = mutableListOf<Int>()
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val queue = Queue()
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var node = this.root
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queue.enqueue(node!!)
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while (queue.getSize() > 0) {
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node = queue.dequeue()
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data.add(node!!.getValue())
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if (node.getLeft() != null) {
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queue.enqueue(node.getLeft()!!)
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}
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if (node.getRight() != null) {
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queue.enqueue(node.getRight()!!)
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}
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}
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return data
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}
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fun getRoot(): TreeNode? {
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return root
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}
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override fun toString(): String {
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return "Root: $root\n"
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}
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}
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package pl.dmichalski.algorithms.data_structures._6_tree_traversal._1_breadth_first_search
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class Node(private var treeNode: TreeNode) {
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private var next: Node?
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init {
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this.next = null
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}
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fun getTreeNode(): TreeNode {
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return treeNode
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}
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fun setTreeNode(treeNode: TreeNode) {
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this.treeNode = treeNode
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}
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fun getNext(): Node? {
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return next
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}
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fun setNext(nextNode: Node?) {
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next = nextNode
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}
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override fun toString(): String {
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return "Node(treeNode='$treeNode', next=$next)"
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}
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}
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package pl.dmichalski.algorithms.data_structures._6_tree_traversal._1_breadth_first_search
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class Queue {
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private var first: Node?
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private var last: Node?
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private var size: Int
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init {
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this.first = null
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this.last = null
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this.size = 0
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}
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fun enqueue(treeNode: TreeNode): Int {
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val node = Node(treeNode)
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if (this.first == null) {
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this.first = node
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this.last = node
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} else {
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this.last!!.setNext(node)
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this.last = node
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}
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return ++this.size
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}
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fun dequeue(): TreeNode? {
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if (this.size == 0) {
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return null
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}
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val temp = this.first
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if (this.first == this.last) {
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this.last = null
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}
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this.first = this.first!!.getNext()
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this.size--
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return temp!!.getTreeNode()
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}
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fun getSize(): Int {
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return this.size
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}
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override fun toString(): String {
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return "First: $first\n" +
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"Last: $last\n" +
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"Size: $size\n"
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}
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}
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package pl.dmichalski.algorithms.data_structures._6_tree_traversal._1_breadth_first_search
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object Runner {
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@JvmStatic
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fun main(args: Array<String>) {
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println("------------------ Initial binary search tree ------------------ ")
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val binarySearchTree = getBinarySearchTree()
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printTree(binarySearchTree)
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println("------------------ Breadth first search traversal ------------------ ")
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val breadthFistSearchTreeValues = binarySearchTree.breadthFistSearch()
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println("Breadth first search values: $breadthFistSearchTreeValues")
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}
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/**
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* It returns BST like this:
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* <pre>
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* 4
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* / \
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* 2 7
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* / / \
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* 1 6 20
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* \
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* 23
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* </pre>
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*/
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private fun getBinarySearchTree(): BinarySearchTree {
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val binarySearchTree = BinarySearchTree()
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binarySearchTree.insert(4)
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binarySearchTree.insert(2)
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binarySearchTree.insert(7)
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binarySearchTree.insert(1)
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binarySearchTree.insert(6)
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binarySearchTree.insert(20)
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binarySearchTree.insert(23)
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return binarySearchTree
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}
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private fun printTree(binarySearchTree: BinarySearchTree) {
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println(binarySearchTree)
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}
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}
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package pl.dmichalski.algorithms.data_structures._6_tree_traversal._1_breadth_first_search
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class TreeNode(private var value: Int) {
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private var left: TreeNode?
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private var right: TreeNode?
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init {
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this.left = null
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this.right = null
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}
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fun getValue(): Int {
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return value
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}
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fun setValue(value: Int) {
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this.value = value
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}
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fun getLeft(): TreeNode? {
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return left
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}
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fun setLeft(left: TreeNode) {
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this.left = left
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}
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fun getRight(): TreeNode? {
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return right
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}
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fun setRight(right: TreeNode) {
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this.right = right
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}
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override fun toString(): String {
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return "Node(value='$value', " +
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"left=$left, " +
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"right=$right)"
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}
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}

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