Optimize copy method from O(N log N) to O(N)

Author: HossamSaberr

src/Containers-AVL-Tree-Tests/CTAVLTreeTest.class.st

@@ -119,6 +119,78 @@ CTAVLTreeTest >> testCopy [
 	self assert: (copiedTree includes: 99)
 ]
 
+{ #category : 'tests' }
+CTAVLTreeTest >> testCopyEmptyTree [
+	| copiedTree |
+	
+	copiedTree := tree copy.
+	
+	self assert: copiedTree isEmpty.
+	self assert: copiedTree size equals: 0.
+	self assert: copiedTree height equals: 0.
+	
+	self deny: copiedTree == tree.
+]
+
+{ #category : 'tests' }
+CTAVLTreeTest >> testCopyLargeTree [
+	| copiedTree elements |
+	
+	elements := (1 to: 1000) asArray shuffled.
+	tree addAll: elements.
+	
+	copiedTree := tree copy.
+	
+	self assert: copiedTree size equals: 1000.
+	self assert: copiedTree height equals: tree height.
+	self assert: copiedTree validate.
+	
+	self assert: copiedTree asArray equals: tree asArray.
+]
+
+{ #category : 'tests' }
+CTAVLTreeTest >> testCopySingleNode [
+	| copiedTree |
+	
+	tree add: 42.
+	copiedTree := tree copy.
+	
+	self assert: copiedTree size equals: 1.
+	self assert: copiedTree height equals: 1.
+	self assert: copiedTree root contents equals: 42.
+	
+	self deny: copiedTree root == tree root.
+	self assert: copiedTree validate.
+]
+
+{ #category : 'tests' }
+CTAVLTreeTest >> testCopyStructureAndIsolation [
+	| copiedTree |
+	
+	tree addAll: #(50 30 70 20 40 60 80).
+	copiedTree := tree copy.
+	
+	self assert: copiedTree size equals: tree size.
+	self assert: copiedTree height equals: tree height.
+	self assert: copiedTree asArray equals: tree asArray.
+	self assert: copiedTree validate.
+	
+	self deny: copiedTree root == tree root.
+	self deny: copiedTree root left == tree root left.
+	
+	copiedTree add: 99.
+	copiedTree remove: 20.
+	
+	self assert: (copiedTree includes: 99).
+	self deny: (tree includes: 99).
+	
+	self deny: (copiedTree includes: 20).
+	self assert: (tree includes: 20).
+	
+	self assert: tree validate.
+	self assert: copiedTree validate.
+]
+
 { #category : 'tests' }
 CTAVLTreeTest >> testDetect [
 

src/Containers-AVL-Tree/CTAVLNilNode.class.st

@@ -37,6 +37,11 @@ CTAVLNilNode >> contents: anObject [
 	"Do nothing for nil node"
 ]
 
+{ #category : 'copying' }
+CTAVLNilNode >> copy [
+	^ self class new
+]
+
 { #category : 'enumerating' }
 CTAVLNilNode >> elementsFrom: min to: max into: aCollection [
 

src/Containers-AVL-Tree/CTAVLNode.class.st

@@ -60,6 +60,19 @@ CTAVLNode >> contents: anObject [
 	contents := anObject
 ]
 
+{ #category : 'copying' }
+CTAVLNode >> copy [
+	| newNode |
+	newNode := self class new.
+	newNode contents: contents.
+	newNode left: left copy.
+	newNode right: right copy.
+
+	newNode instVarNamed: 'height' put: height. 
+
+	^ newNode
+]
+
 { #category : 'enumerating' }
 CTAVLNode >> elementsFrom: min to: max into: aCollection [
 

src/Containers-AVL-Tree/CTAVLTree.class.st

@@ -92,15 +92,6 @@ CTAVLTree >> collect: aBlock [
 	^ result
 ]
 
-{ #category : 'copying' }
-CTAVLTree >> copy [
-
-	| newTree |
-	newTree := self class new.
-	self inOrderDo: [ :each | newTree add: each ].
-	^ newTree
-]
-
 { #category : 'enumerating' }
 CTAVLTree >> detect: aBlock ifNone: absentBlock [
 
@@ -236,6 +227,12 @@ CTAVLTree >> last [
 	^ self findMax
 ]
 
+{ #category : 'copying' }
+CTAVLTree >> postCopy [
+	super postCopy.
+	root := root copy.
+]
+
 { #category : 'enumerating' }
 CTAVLTree >> postOrderDo: aBlock [