Added Trie

examples/trie/trie.go

@@ -0,0 +1,32 @@
+// Copyright (c) 2015, Emir Pasic. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"fmt"
+	trie "github.com/emirpasic/gods/trees/trie"
+)
+
+func main() {
+	fmt.Println("a")
+	t := trie.New()
+	words := []string{"sam", "john", "tim", "jose", "rose",
+		"cat", "dog", "dogg", "roses"}
+	for i := 0; i < len(words); i++ {
+		t.Insert(words[i])
+	}
+	wordsToFind := []string{
+		"sam", "john", "tim", "jose", "rose",
+		"cat", "dog", "dogg", "roses", "rosess", "ans", "san",
+	}
+	for i := 0; i < len(wordsToFind); i++ {
+		found := t.Contains(wordsToFind[i])
+		if found {
+			fmt.Printf("Word \"%s\" found in trie\n", wordsToFind[i])
+		} else {
+			fmt.Printf("Word \"%s\" not found in trie\n", wordsToFind[i])
+		}
+	}
+}

lists/arraylist/arraylist.go

@@ -50,6 +50,22 @@ func (list *List) Add(values ...interface{}) {
 	}
 }
 
+// Reverse reverse the list
+func (list *List) Reverse() {
+	var s = list.Size()
+
+	if s < 1 {
+		return
+	}
+
+	var temp = list.elements[0]
+	for i := 0; i < s / 2; i++ {
+		temp = list.elements[i]
+		list.elements[i] = list.elements[s - 1 - i]
+		list.elements[s - 1 - i] = temp
+	}
+}
+
 // Get returns the element at index.
 // Second return parameter is true if index is within bounds of the array and array is not empty, otherwise false.
 func (list *List) Get(index int) (interface{}, bool) {
@@ -126,6 +142,17 @@ func (list *List) Size() int {
 	return list.size
 }
 
+// Count returns number of occurences of a given value in the list
+func (list *List) Count(value interface{}) int {
+	var count = 0
+	for i := 0; i < list.Size(); i++ {
+		if list.elements[i] == value {
+			count++
+		}
+	}
+	return count
+} 
+
 // Clear removes all elements from the list.
 func (list *List) Clear() {
 	list.size = 0
@@ -183,6 +210,15 @@ func (list *List) Set(index int, value interface{}) {
 	list.elements[index] = value
 }
 
+// Replace replaces all occurences of "value" by "by"
+func (list *List) Replace(value interface{}, by interface{}) {
+	for i := 0; i < list.Size(); i++ {
+		if list.elements[i] == value {
+			list.elements[i] = by
+		}
+	}
+}
+
 // String returns a string representation of container
 func (list *List) String() string {
 	str := "ArrayList\n"

lists/arraylist/arraylist_test.go

@@ -51,6 +51,60 @@ func TestListAdd(t *testing.T) {
 	}
 }
 
+func TestListReverse(t *testing.T) {
+	list := New()
+	list.Add("a", "b", "c")
+	list.Reverse()
+	if actualValue, ok := list.Get(0); actualValue != "c" || !ok {
+		t.Errorf("Got %v expected %v", actualValue, "c")
+	}
+	if actualValue, ok := list.Get(1); actualValue != "b" || !ok {
+		t.Errorf("Got %v expected %v", actualValue, "b")
+	}
+	if actualValue, ok := list.Get(2); actualValue != "a" || !ok {
+		t.Errorf("Got %v expected %v", actualValue, "a")
+	}
+}
+
+func TestListCount(t *testing.T){
+	list := New()
+	list.Add("a", "b", "c", "b", "b", "a", "d", "e", "f", "e")
+	if actualValue := list.Count("a"); actualValue != 2 {
+		t.Errorf("Got %v expected %v", actualValue, 2)
+	}
+	if actualValue := list.Count("b"); actualValue != 3 {
+		t.Errorf("Got %v expected %v", actualValue, 3)
+	}
+	if actualValue := list.Count("c"); actualValue != 1 {
+		t.Errorf("Got %v expected %v", actualValue, 1)
+	}
+	if actualValue := list.Count("z"); actualValue != 0 {
+		t.Errorf("Got %v expected %v", actualValue, 0)
+	}
+}
+
+func TestListReplace(t *testing.T){
+	list := New()
+	list.Add("a", "b", "c", "c", "a")
+	list.Replace("a", "z")
+	if actualValue, ok := list.Get(0); actualValue != "z" || !ok {
+		t.Errorf("Got %v expected %v", actualValue, "z")
+	}
+	if actualValue, ok := list.Get(1); actualValue != "b" || !ok {
+		t.Errorf("Got %v expected %v", actualValue, "b")
+	}
+	if actualValue, ok := list.Get(2); actualValue != "c" || !ok {
+		t.Errorf("Got %v expected %v", actualValue, "c")
+	}
+	if actualValue, ok := list.Get(3); actualValue != "c" || ok {
+		t.Errorf("Got %v expected %v", actualValue, "c")
+	}
+	list.Remove(0)
+	if actualValue, ok := list.Get(0); actualValue != "z" || !ok {
+		t.Errorf("Got %v expected %v", actualValue, "z")
+	}
+}
+
 func TestListIndexOf(t *testing.T) {
 	list := New()
 

lists/lists.go

@@ -19,6 +19,9 @@ type List interface {
 	Get(index int) (interface{}, bool)
 	Remove(index int)
 	Add(values ...interface{})
+	Count(value interface{})
+	Reverse()
+	Replace(value interface{}, by interface{})
 	Contains(values ...interface{}) bool
 	Sort(comparator utils.Comparator)
 	Swap(index1, index2 int)

trees/trie/iterator.go

@@ -0,0 +1,83 @@
+package trie
+
+import "github.com/emirpasic/gods/containers"
+
+func assertIteratorImplementation() {
+	var _ containers.ReverseIteratorWithIndex = (*Iterator)(nil)
+}
+
+// Iterator holding the iterator's state
+type Iterator struct {
+	words []string
+	trie *Trie
+	index int
+}
+
+// Iterator returns a stateful iterator whose values can be fetched by an index.
+func (trie *Trie) Iterator() Iterator {
+	s := make([]string, 10)
+	findWords(trie.root, "", s)
+	return Iterator{words:s, trie: trie, index:-1}
+}
+
+// Next moves the iterator to the next element and returns true if there was a next element in the container.
+// If Next() returns true, then next element's index and value can be retrieved by Index() and Value().
+// If Next() was called for the first time, then it will point the iterator to the first element if it exists.
+// Modifies the state of the iterator.
+func (iterator *Iterator) Next() bool {
+	if iterator.index < iterator.heap.Size() {
+		iterator.index++
+	}
+	return iterator.words.withinRange(iterator.index)
+}
+
+// Prev moves the iterator to the previous element and returns true if there was a previous element in the container.
+// If Prev() returns true, then previous element's index and value can be retrieved by Index() and Value().
+// Modifies the state of the iterator.
+func (iterator *Iterator) Prev() bool {
+	if iterator.index >= 0 {
+		iterator.index--
+	}
+	return iterator.words.withinRange(iterator.index)
+}
+
+// Value returns the current element's value.
+// Does not modify the state of the iterator.
+func (iterator *Iterator) Value() interface{} {
+	value, _ := iterator.words.list.Get(iterator.index)
+	return value
+}
+
+// Index returns the current element's index.
+// Does not modify the state of the iterator.
+func (iterator *Iterator) Index() int {
+	return iterator.index
+}
+
+// Begin resets the iterator to its initial state (one-before-first)
+// Call Next() to fetch the first element if any.
+func (iterator *Iterator) Begin() {
+	iterator.index = -1
+}
+
+// End moves the iterator past the last element (one-past-the-end).
+// Call Prev() to fetch the last element if any.
+func (iterator *Iterator) End() {
+	iterator.index = iterator.words.Size()
+}
+
+// First moves the iterator to the first element and returns true if there was a first element in the container.
+// If First() returns true, then first element's index and value can be retrieved by Index() and Value().
+// Modifies the state of the iterator.
+func (iterator *Iterator) First() bool {
+	iterator.Begin()
+	return iterator.Next()
+}
+
+// Last moves the iterator to the last element and returns true if there was a last element in the container.
+// If Last() returns true, then last element's index and value can be retrieved by Index() and Value().
+// Modifies the state of the iterator.
+func (iterator *Iterator) Last() bool {
+	iterator.End()
+	return iterator.Prev()
+}

trees/trie/serialization.go

@@ -0,0 +1,30 @@
+package trie
+
+import "github.com/emirpasic/gods/containers"
+
+func assertSerializationImplementation() {
+	var _ containers.JSONSerializer = (*Trie)(nil)
+	var _ containers.JSONDeserializer = (*Trie)(nil)
+}
+
+// ToJSON outputs the JSON representation of the heap.
+func (t *Trie) ToJSON() ([]byte, error) {
+	elements := make([]interface{})
+	it := trie.Iterator(t)
+	for it.Next() {
+		elements.append(it.Value())
+	}
+	return json.Marshal(&elements)
+}
+
+// FromJSON populates the tree from the input JSON representation.
+func (t *Trie) FromJSON(data []byte) error {
+	elements := make([]interface{})
+	err := json.Unmarshal(data, &elements)
+	if err == nil {
+		for _, value := range elements {
+			t.insert(value)
+		}
+	}
+	return err
+}

trees/trie/trie.go

@@ -0,0 +1,107 @@
+package trie
+
+const (
+	// AlphabetSize total characters in english alphabet
+	AlphabetSize = 26
+)
+
+<<<<<<< HEAD
+type TrieNode struct {
+	children  [AlphabetSize]*TrieNode
+	isWordEnd bool
+}
+
+type Trie struct {
+	root *TrieNode
+}
+
+// New returns a pointer pointing to a new Trie
+func New() *Trie {
+	return &Trie{
+		root: &TrieNode{},
+	}
+}
+
+// Insert inserts a word into the Trie
+func (t *Trie) Insert(word string) {
+=======
+type trieNode struct {
+	children  [AlphabetSize]*trieNode
+	isWordEnd bool
+}
+
+type trie struct {
+	root       *trieNode
+	nodesCount int
+}
+
+// New returns a pointer pointing to a new trie
+func New() *trie {
+	return &trie{
+		root: &trieNode{},
+	}
+}
+
+// Insert inserts a word into the trie
+func (t *trie) Insert(word string) {
+>>>>>>> 2896b350131353759aacf42da7047972425068eb
+	wordLength := len(word)
+	current := t.root
+	for i := 0; i < wordLength; i++ {
+		index := word[i] - 'a'
+		if current.children[index] == nil {
+<<<<<<< HEAD
+			current.children[index] = &TrieNode{}
+=======
+			current.children[index] = &trieNode{}
+			t.nodesCount++
+>>>>>>> 2896b350131353759aacf42da7047972425068eb
+		}
+		current = current.children[index]
+	}
+	current.isWordEnd = true
+}
+
+<<<<<<< HEAD
+// Contains checks whether the Trie has the given word or not
+func (t *Trie) Contains(word string) bool {
+=======
+// Contains checks whether the trie has the given word or not
+func (t *trie) Contains(word string) bool {
+>>>>>>> 2896b350131353759aacf42da7047972425068eb
+	wordLength := len(word)
+	current := t.root
+	for i := 0; i < wordLength; i++ {
+		index := word[i] - 'a'
+		if current.children[index] == nil {
+			return false
+		}
+		current = current.children[index]
+	}
+
+	return current.isWordEnd
+<<<<<<< HEAD
+}
+
+func (trie *TrieNode, value string, values []string) findWords(){
+	for i := 0; i< 26 ; i++ {
+		if trie.isWordEnd {
+			values.append(value+string(i+'a'))
+		}
+		if trie.children[i] != nil {
+			findWords(trie.children[i], value+string(i+'a'), values)
+		}
+	}
+=======
+}
+
+// NodesCount returns number of nodes in the tree.
+func (t *trie) NodesCount() int {
+	return t.nodesCount
+}
+
+// Empty returns true if tree does not contain any nodes except for root
+func (t *trie) Empty() bool {
+	return t.nodesCount == 0
+>>>>>>> 2896b350131353759aacf42da7047972425068eb
+}