How to GET a Cup of Coffee

 An interesting article about REST
How to GET a Cup of Coffee

Trie: Second Implementation in Groovy

This is another version of Trie implementation in my previous post. The new one comes with a flag to identify a complete word.

	class Node {
	/*data to be save*/
	def data
	/*child nodes of this node*/
	def children = [:]
	/*any key finshied in this node? (end of a word)*/
	def flag = false
	}
	class Trie {
	/*Root node with empty data - edited*/
	def root = new Node(data:'')
	def insert(key) {
	def node = root
	key.each {
	/*find the relevant child node*/
	def child = node.children[it]
	/*if child does not exist, creates it*/
	if (child == null) {
	child = node.children[it] = new Node(data:it)
	}
	node = child
	}
	/*flag the last node as end of this word*/
	node.flag = true
	}
	def search(key) {
	def node = root
	def x = key.find {
	node = node.children[it]
	/*if the child does not exist, key does not exist in trie*/
	node == null
	}
	/*check if the chain of characters exists AND its a complete word (flag == true)*/
	return x == null && node.flag
	}
	def disply() {
	print(root, '')
	}
	private print(node, prefix) {
	/*if its a complete word, print it*/
	if (node.flag) {
	println "${prefix}${node.data}"
	}
	/*visit children, to find rest of words*/
	node.children.values().each {
	print(it, prefix + node.data)
	}
	}
	}
	def t = new Trie()
	t.insert("trie")
	t.insert("tree")
	t.insert("i")
	t.insert("it")
	t.insert("ite")
	assert false == t.search("t")
	assert false == t.search("tr")
	assert false == t.search("tri")
	assert true == t.search("trie")
	assert false == t.search("tre")
	assert true == t.search("tree")
	assert true == t.search("i")
	assert true == t.search("it")
	assert true == t.search("ite")
	assert false == t.search("triex")
	assert false == t.search("treexx")
	assert false == t.search("ix")
	t.disply()

view raw gistfile1.groovy hosted with ❤ by GitHub

Groovy : Trie Implementation

From Wikipedia:

In computer science, a trie, or prefix tree, is an ordered tree data structure that is used to store an associative array where the keys are usually strings. Unlike a binary search tree, no node in the tree stores the key associated with that node; instead, its position in the tree defines the key it is associated with. All the descendants of a node have a common prefix of the string associated with that node, and the root is associated with the empty string. Values are normally not associated with every node, only with leaves and some inner nodes that correspond to keys of interest.

	class Node {
	/*data to be save*/
	def data
	/*child nodes of this node*/
	def children = [:]
	}
	class Trie {
	/*root node with empty data*/
	def root = new Node(data:'')
	def insert(key) {
	def node = root
	key.each {
	/*find the relevant child node*/
	def child = node.children[it]
	/*if child does not exist, creates it*/
	if (child == null) {
	child = node.children[it] = new Node(data:it)
	}
	node = child
	}
	}
	def search(key) {
	def node = root
	def x = key.find {
	node = node.children[it]
	/*if the child does not exist, key does not exist in trie*/
	node == null
	}
	return x == null
	}
	}
	def t = new Trie()
	t.insert("trie")
	t.insert("tree")
	t.insert("i")
	t.insert("it")
	t.insert("ite")
	assert true == t.search("t")
	assert true == t.search("tr")
	assert true == t.search("tri")
	assert true == t.search("trie")
	assert true == t.search("tre")
	assert true == t.search("tree")
	assert true == t.search("i")
	assert true == t.search("it")
	assert true == t.search("ite")
	assert false == t.search("triex")
	assert false == t.search("treexx")
	assert false == t.search("ix")

view raw gistfile1.groovy hosted with ❤ by GitHub