From 8c29827097d519514ec734476614279c7e2330d1 Mon Sep 17 00:00:00 2001
From: konradkelly <konradky@gmail.com>
Date: Wed, 21 May 2025 11:57:00 -0700
Subject: [PATCH 1/3] instantiated TreeNodes and preOrder method

---
 src/Traversal.java | 27 +++++++++++++++++++++++++++
 src/TreeNode.java  |  7 ++++++-
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/Traversal.java b/src/Traversal.java
index 8da0f79..a483658 100644
--- a/src/Traversal.java
+++ b/src/Traversal.java
@@ -1,5 +1,32 @@
 public class Traversal {
   public static void main(String[] args) {
+    TreeNode root = new TreeNode(10);
+    //System.out.println(root.data);
 
+    root.left = new TreeNode(9);
+    root.right = new TreeNode(15);
+    //System.out.println(root.right.data);
+    
+    root.left.left = new TreeNode(5);
+    root.left.right = new TreeNode(2);
+
+    root.right = new TreeNode(15);
+    root.right.left = new TreeNode(-3);
+    root.right.right = new TreeNode(5);
+
+    root.right.right.right = new TreeNode(22);
+
+    preOrder(root);
+  }
+  public static void preOrder(TreeNode current) {
+    //if null: return
+    if (current == null) return;
+    
+    //print data
+    System.out.println(current.data);
+    //search left
+    preOrder(current.left);
+    //search right
+    preOrder(current.right);
   }
 }
diff --git a/src/TreeNode.java b/src/TreeNode.java
index acd9639..36e0468 100644
--- a/src/TreeNode.java
+++ b/src/TreeNode.java
@@ -1,4 +1,9 @@
 public class TreeNode {
+    public int data;
+    public TreeNode left;
+    public TreeNode right;
 
-  
+    public TreeNode(int data) {
+        this.data = data;
+    }
 }
\ No newline at end of file

From 74015c7b52ec2a35b4d0c1cede13c4f1c0824d90 Mon Sep 17 00:00:00 2001
From: konradkelly <konradky@gmail.com>
Date: Thu, 12 Feb 2026 14:52:32 -0800
Subject: [PATCH 2/3] refactor class constructor and implement preOrder,
 postOrder, and inOrder methods

---
 src/Traversal.java | 62 +++++++++++++++++++++++++++-------------------
 src/TreeNode.java  | 10 +++++---
 2 files changed, 42 insertions(+), 30 deletions(-)

diff --git a/src/Traversal.java b/src/Traversal.java
index a483658..a06781f 100644
--- a/src/Traversal.java
+++ b/src/Traversal.java
@@ -1,32 +1,42 @@
 public class Traversal {
   public static void main(String[] args) {
-    TreeNode root = new TreeNode(10);
-    //System.out.println(root.data);
+    TreeNode root = new TreeNode(10, null, null);
+    //System.out.println(root.value);
+    root.left = new TreeNode(9, null, null);
+    //System.out.println(root.left.value);
+    root.left.left = new TreeNode(5, null, null);
+    //System.out.println(root.left.left.value);
+    root.left.right = new TreeNode(2, null, null);
+    //System.out.println(root.left.right.value);
 
-    root.left = new TreeNode(9);
-    root.right = new TreeNode(15);
-    //System.out.println(root.right.data);
-    
-    root.left.left = new TreeNode(5);
-    root.left.right = new TreeNode(2);
+    root.right = new TreeNode(15, null, null);
+    root.right.left = new TreeNode(-3, null, null);
+    root.right.right = new TreeNode(5, null,null);
+    root.right.right.right = new TreeNode(22, null, null);
 
-    root.right = new TreeNode(15);
-    root.right.left = new TreeNode(-3);
-    root.right.right = new TreeNode(5);
-
-    root.right.right.right = new TreeNode(22);
-
-    preOrder(root);
+    //preOrder(root);
+    //postOrder(root);
+    inOrder(root);
+  }
+  //Print a tree rooted at the given node in pre-order
+  public static void preOrder(TreeNode node) {
+    if (node == null) return;
+    System.out.println(node.value);
+    preOrder(node.left);
+    preOrder(node.right);
   }
-  public static void preOrder(TreeNode current) {
-    //if null: return
-    if (current == null) return;
-    
-    //print data
-    System.out.println(current.data);
-    //search left
-    preOrder(current.left);
-    //search right
-    preOrder(current.right);
+  
+  public static void postOrder(TreeNode node) {
+    if (node == null) return;
+    postOrder(node.left);
+    postOrder(node.right);
+    System.out.println(node.value);
+  }
+
+  public static void inOrder(TreeNode node) {
+    if (node == null) return;
+    inOrder(node.left);
+    System.out.println(node.value);
+    inOrder(node.right);
   }
-}
+}
\ No newline at end of file
diff --git a/src/TreeNode.java b/src/TreeNode.java
index 36e0468..5c01817 100644
--- a/src/TreeNode.java
+++ b/src/TreeNode.java
@@ -1,9 +1,11 @@
 public class TreeNode {
-    public int data;
+    public int value;
     public TreeNode left;
     public TreeNode right;
 
-    public TreeNode(int data) {
-        this.data = data;
-    }
+    public TreeNode(int value, TreeNode left, TreeNode right) {
+        this.value = value;
+        this.left = left;
+        this.right = right;
+    }    
 }
\ No newline at end of file

From b8f23506adc02e77fea0df0b71c8adab241ba277 Mon Sep 17 00:00:00 2001
From: konradkelly <konradky@gmail.com>
Date: Tue, 17 Feb 2026 14:40:00 -0800
Subject: [PATCH 3/3] implemented printGreater and countNodes methods

---
 src/Traversal.java | 118 ++++++++++++++++++++++++++++++++++++++++-----
 src/TreeNode.java  |  10 ++--
 2 files changed, 111 insertions(+), 17 deletions(-)

diff --git a/src/Traversal.java b/src/Traversal.java
index a06781f..20f862b 100644
--- a/src/Traversal.java
+++ b/src/Traversal.java
@@ -1,39 +1,133 @@
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.Map;
+import java.util.Queue;
+import java.util.Stack;
+
 public class Traversal {
   public static void main(String[] args) {
-    TreeNode root = new TreeNode(10, null, null);
+    TreeNode<Integer> root = new TreeNode<Integer>(10, null, null);
     //System.out.println(root.value);
-    root.left = new TreeNode(9, null, null);
+    root.left = new TreeNode<Integer>(9, null, null);
     //System.out.println(root.left.value);
-    root.left.left = new TreeNode(5, null, null);
+    root.left.left = new TreeNode<Integer>(5, null, null);
     //System.out.println(root.left.left.value);
-    root.left.right = new TreeNode(2, null, null);
+    root.left.right = new TreeNode<Integer>(2, null, null);
     //System.out.println(root.left.right.value);
 
-    root.right = new TreeNode(15, null, null);
-    root.right.left = new TreeNode(-3, null, null);
-    root.right.right = new TreeNode(5, null,null);
-    root.right.right.right = new TreeNode(22, null, null);
+    root.right = new TreeNode<Integer>(15, null, null);
+    root.right.left = new TreeNode<Integer>(-3, null, null);
+    root.right.right = new TreeNode<Integer>(5, null,null);
+    root.right.right.right = new TreeNode<Integer>(22, null, null);
+
+    TreeNode<String> stringRoot = new TreeNode<String>("hello", null, null);
+    stringRoot.right = new TreeNode<String>("hello", null, null);
+    stringRoot.left = new TreeNode<String>("I", null, null);
+    stringRoot.right.left = new TreeNode<String>("am", null, null);
+    stringRoot.left.right = new TreeNode<String>("am", null, null);
+
+    TreeNode<Integer> megaRoot = new TreeNode<Integer>(1, null, null);
+    TreeNode<Integer> current = megaRoot;
+    
+    for (int i = 2; i <= 50000; i++) {
+      current.right = new TreeNode<Integer>(i, null, null);
+      current = current.right;
+    }
+
+    levelOrder(root);
+    //preOrderIter(megaRoot);
+
+    // System.out.println("Preorder recursive");
+    // preOrder(root);
+    //System.out.println("Prorder iterative");
+    //preOrderIter(root);
 
     //preOrder(root);
     //postOrder(root);
-    inOrder(root);
+    //inOrder(root);
+    //printGreater(root, 7);
+    //System.out.println(countNodes(root));
+    
+    //System.out.println(toMap(stringRoot));
+  }
+  
+
+  public static <T> void preOrderIter(TreeNode<T> node) {
+    Stack<TreeNode<T>> stack = new Stack<>();
+    stack.push(node);
+    
+    while (!stack.isEmpty()) {
+      TreeNode<T> current = stack.pop();
+      if (current == null) {
+        continue;
+      }
+      System.out.println(current.value);
+      stack.push(current.right);
+      stack.push(current.left);
+    }
+  }
+
+    public static <T> void levelOrder(TreeNode<T> node) {
+    Queue<TreeNode<T>> queue = new LinkedList<>();
+      queue.add(node);
+    
+    while (!queue.isEmpty()) {
+      TreeNode<T> current = queue.poll();
+      if (current == null) {
+        continue;
+      }
+      System.out.println(current.value);
+      queue.add(current.left);
+      queue.add(current.right);
+    }
+  }
+
+  public static <T> Map<T, Integer> toMap(TreeNode<T> node) {
+    Map<T, Integer> counts = new HashMap<>();
+    toMap(node, counts);
+    return counts;
+  }
+  private static <T> void toMap(TreeNode<T> node, Map<T, Integer> counts) {
+    if (node == null) {
+      return;
+    }
+    counts.put(node.value, counts.getOrDefault(node.value, 0) + 1);
+    toMap(node.left, counts);
+    toMap(node.right, counts);
+  }
+
+  public static int countNodes(TreeNode<?> node) {
+    return node == null ? 0 : 1 + countNodes(node.left) + countNodes(node.right);
+    // int leftCount = countNodes(node.left);
+    // int rightCount = countNodes(node.right);
+    // int overallCount = leftCount + rightCount + 1;
+    // return overallCount;
+  }
+
+  public static void printGreater(TreeNode<Integer> node, int threshold) {
+    if (node == null) return;
+    if (node.value > threshold) {
+      System.out.println(node.value);
+    }
+    printGreater(node.left, threshold);
+    printGreater(node.right, threshold);
   }
   //Print a tree rooted at the given node in pre-order
-  public static void preOrder(TreeNode node) {
+  public static void preOrder(TreeNode<?> node) {
     if (node == null) return;
     System.out.println(node.value);
     preOrder(node.left);
     preOrder(node.right);
   }
   
-  public static void postOrder(TreeNode node) {
+  public static <T> void postOrder(TreeNode<T> node) {
     if (node == null) return;
     postOrder(node.left);
     postOrder(node.right);
     System.out.println(node.value);
   }
 
-  public static void inOrder(TreeNode node) {
+  public static <E> void inOrder(TreeNode<E> node) {
     if (node == null) return;
     inOrder(node.left);
     System.out.println(node.value);
diff --git a/src/TreeNode.java b/src/TreeNode.java
index 5c01817..7d0ee3a 100644
--- a/src/TreeNode.java
+++ b/src/TreeNode.java
@@ -1,9 +1,9 @@
-public class TreeNode {
-    public int value;
-    public TreeNode left;
-    public TreeNode right;
+public class TreeNode<T> {
+    public T value;
+    public TreeNode<T> left;
+    public TreeNode<T> right;
 
-    public TreeNode(int value, TreeNode left, TreeNode right) {
+    public TreeNode(T value, TreeNode<T> left, TreeNode<T> right) {
         this.value = value;
         this.left = left;
         this.right = right;