Pre-allocate memory to reduce the number of allocations (#272)

datastructure/link/doublylink.go

@@ -209,7 +209,7 @@ func (dl *DoublyLink[T]) Size() int {
 
 // Values return slice of all doubly linklist node value
 func (dl *DoublyLink[T]) Values() []T {
-	result := []T{}
+	result := make([]T, 0, dl.length)
 	current := dl.Head
 	for current != nil {
 		result = append(result, current.Value)

datastructure/link/singlylink.go

@@ -212,7 +212,7 @@ func (sl *SinglyLink[T]) Size() int {
 
 // Values return slice of all singly linklist node value
 func (sl *SinglyLink[T]) Values() []T {
-	result := []T{}
+	result := make([]T, 0, sl.length)
 	current := sl.Head
 	for current != nil {
 		result = append(result, current.Value)

datastructure/queue/arrayqueue.go

@@ -31,7 +31,7 @@ func NewArrayQueue[T any](capacity int) *ArrayQueue[T] {
 
 // Data return slice of queue data
 func (q *ArrayQueue[T]) Data() []T {
-	items := []T{}
+	items := make([]T, 0, q.tail-q.head)
 	for i := q.head; i < q.tail; i++ {
 		items = append(items, q.data[i])
 	}

datastructure/queue/linkedqueue.go

@@ -27,7 +27,7 @@ func NewLinkedQueue[T any]() *LinkedQueue[T] {
 
 // Data return slice of queue data
 func (q *LinkedQueue[T]) Data() []T {
-	res := []T{}
+	res := make([]T, 0, q.length)
 	current := q.head
 
 	for current != nil {

datastructure/stack/linkedstack.go

@@ -24,7 +24,7 @@ func NewLinkedStack[T any]() *LinkedStack[T] {
 
 // Data return stack data
 func (s *LinkedStack[T]) Data() []T {
-	res := []T{}
+	res := make([]T, 0, s.length)
 	current := s.top
 
 	for current != nil {

datastructure/tree/tree_internal.go

@@ -147,7 +147,7 @@ func printTreeNodes[T any](nodes []*datastructure.TreeNode[T], level, maxLevel i
 
 	printSpaces(firstSpaces)
 
-	newNodes := []*datastructure.TreeNode[T]{}
+	newNodes := make([]*datastructure.TreeNode[T], 0, len(nodes)*2)
 	for _, node := range nodes {
 		if node != nil {
 			fmt.Printf("%v", node.Value)