From ae0d399d9b6a4d29285002bc3836be82f8c7df70 Mon Sep 17 00:00:00 2001
From: Michael OBrien <michael@obrienlabs.org>
Date: Sun, 11 Feb 2024 11:33:30 -0500
Subject: [PATCH] #2 - traversal using nodes

---
 .../compsci/collections/BinaryTree.java       |  7 +++---
 .../compsci/collections/BinaryTreeImpl.java   | 25 +++++++++++++++----
 .../compsci/collections/BinaryTreeTest.java   |  6 +++--
 3 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/compsci-lib/src/main/java/dev/obrienlabs/compsci/collections/BinaryTree.java b/compsci-lib/src/main/java/dev/obrienlabs/compsci/collections/BinaryTree.java
index e8ad257..580cfed 100644
--- a/compsci-lib/src/main/java/dev/obrienlabs/compsci/collections/BinaryTree.java
+++ b/compsci-lib/src/main/java/dev/obrienlabs/compsci/collections/BinaryTree.java
@@ -12,7 +12,8 @@ public interface BinaryTree<T extends Comparable<? super T>> {
 	T getData();
 	boolean search(T value);
 	Integer depth();
-	List<T> inOrderTraversal();
-	List<T> inOrderTraversalHelper(List<T> list);
-	
+	List<BinaryTree<T>> inOrderTraversal();
+	List<BinaryTree<T>> inOrderTraversalHelper(List<BinaryTree<T>> list);
+	List<BinaryTree<T>> inOrderTraversalOnlyLeft();
+	List<BinaryTree<T>> inOrderTraversalOnlyLeftHelper(List<BinaryTree<T>> list);	
 }
diff --git a/compsci-lib/src/main/java/dev/obrienlabs/compsci/collections/BinaryTreeImpl.java b/compsci-lib/src/main/java/dev/obrienlabs/compsci/collections/BinaryTreeImpl.java
index 55ca297..0bf4a53 100644
--- a/compsci-lib/src/main/java/dev/obrienlabs/compsci/collections/BinaryTreeImpl.java
+++ b/compsci-lib/src/main/java/dev/obrienlabs/compsci/collections/BinaryTreeImpl.java
@@ -24,19 +24,34 @@ public T getData() {
 	}
 	
 	@Override
-	public List<T> inOrderTraversal() {
-		return inOrderTraversalHelper(new ArrayList<T>());
+	public List<BinaryTree<T>> inOrderTraversal() {
+		return inOrderTraversalHelper(new ArrayList<BinaryTree<T>>());
 	}
 
 	@Override
-	public List<T> inOrderTraversalHelper(List<T> list) {
+	public List<BinaryTree<T>> inOrderTraversalHelper(List<BinaryTree<T>> list) {
 		if(null != left)
 			left.inOrderTraversalHelper(list);
-		list.add(data);
+		list.add(this);
 		if(null != right)
 			right.inOrderTraversalHelper(list);
 		return list;
 	}
+
+	@Override
+	public List<BinaryTree<T>> inOrderTraversalOnlyLeft() {
+		return inOrderTraversalOnlyLeftHelper(new ArrayList<BinaryTree<T>>());
+	}
+
+	@Override
+	public List<BinaryTree<T>> inOrderTraversalOnlyLeftHelper(List<BinaryTree<T>> list) {
+		if(null != left)
+			left.inOrderTraversalOnlyLeftHelper(list);
+		list.add(this);
+		if(null != right)
+			right.inOrderTraversalOnlyLeftHelper(list);
+		return list;
+	}	
 	
 	@Override
 	public void add(T value) {
@@ -80,7 +95,7 @@ public boolean search(T value) {
 	@Override
 	public String toString() {
 		StringBuffer buffer = new StringBuffer();
-		inOrderTraversal().stream().forEach(i -> buffer.append(i).append(","));
+		inOrderTraversal().stream().forEach(i -> buffer.append(i.getData()).append(","));
 		return buffer.toString();
 	}
 	
diff --git a/compsci-lib/src/test/java/dev/obrienlabs/compsci/collections/BinaryTreeTest.java b/compsci-lib/src/test/java/dev/obrienlabs/compsci/collections/BinaryTreeTest.java
index 443e4b7..e2e8077 100644
--- a/compsci-lib/src/test/java/dev/obrienlabs/compsci/collections/BinaryTreeTest.java
+++ b/compsci-lib/src/test/java/dev/obrienlabs/compsci/collections/BinaryTreeTest.java
@@ -18,12 +18,14 @@ public class BinaryTreeTest {
 	@Test
 	public void testContructor() {
 		BinaryTree<Integer> tree = new BinaryTreeImpl<Integer>();
-		List<Integer> list = tree.inOrderTraversal();
-		assertNotNull(list);
+
 		
 		// Add a list of numbers
 		List<Integer> numbersToInsert = Stream.of(8,16,32,64,48,2,128).collect(Collectors.toList());
 		tree.add(numbersToInsert);
+		
+		List<BinaryTree<Integer>> list = tree.inOrderTraversal();
+		assertNotNull(list);
 
 		BinaryTree<Integer> subTree = tree.getRight();
 		assertNotNull(subTree);