From effb467dc03c97b22460909d190e6dd247946a6b Mon Sep 17 00:00:00 2001
From: schrom01 <schrom01@students.zhaw.ch>
Date: Sun, 23 Oct 2022 19:05:25 +0200
Subject: [PATCH] Solved Task 5

---
 src/ch/zhaw/ads/TreeTraversal.java | 81 +++++++++++++++++++-----------
 1 file changed, 51 insertions(+), 30 deletions(-)

diff --git a/src/ch/zhaw/ads/TreeTraversal.java b/src/ch/zhaw/ads/TreeTraversal.java
index 1fdecef..99ca0a8 100644
--- a/src/ch/zhaw/ads/TreeTraversal.java
+++ b/src/ch/zhaw/ads/TreeTraversal.java
@@ -1,19 +1,32 @@
 package ch.zhaw.ads;
 
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Stack;
+import java.util.*;
 
 public class TreeTraversal<T extends Comparable<T>> implements Traversal<T> {
+    @SuppressWarnings("unchecked")
     private final TreeNode<T> root;
 
     public TreeTraversal(TreeNode<T> root) {
         this.root = root;
     }
 
-    @Override
-    public void interval(T min, T max, Visitor<T> vistor) {
 
+    @Override
+    public void interval(T min, T max, Visitor<T> vis) {
+        Queue<TreeNode<T>> queue =  new LinkedList<TreeNode<T>>();
+        queue.add(root);
+        while(!queue.isEmpty()){
+            TreeNode<T> node = queue.poll();
+            if(node.getValue().compareTo(min) >= 0 && node.getValue().compareTo(max) <= 0)
+            vis.visit(node.getValue());
+            if(node.left != null && (node.right == null || node.right.getValue().compareTo(min) >= 0)){
+                queue.add(node.left);
+            }
+            if(node.right != null && (node.left == null || node.left.getValue().compareTo(max) <= 0)){
+                queue.add(node.right);
+            }
+
+        }
     }
 
     public void inorder(Visitor<T> vis) {
@@ -31,7 +44,7 @@ public class TreeTraversal<T extends Comparable<T>> implements Traversal<T> {
     }
 
     public void preorder(Visitor<T> vis) {
-        Stack<TreeNode<T>> stack = new Stack();
+        Stack<TreeNode<T>> stack = new Stack<TreeNode<T>>();
         TreeNode<T> node = root;
         stack.push(node);
         while(!stack.isEmpty()) {
@@ -47,34 +60,42 @@ public class TreeTraversal<T extends Comparable<T>> implements Traversal<T> {
     }
 
     public void postorder(Visitor<T> vis) {
-        postorderRec(vis, root);
-    }
-
-    public void postorderRec(Visitor<T> vis, TreeNode<T> root){
-        inorderRec(vis, root.left);
-        inorderRec(vis, root.right);
-        vis.visit(root.getValue());
+        Stack<TreeNode<T>> stack = new Stack<TreeNode<T>>();
+        TreeNode<T> root = this.root;
+        do {
+            while(root != null){
+                if(root.right != null)  {
+                    stack.push(root.right);
+                }
+                stack.push(root);
+                root = root.left;
+            }
+            root = stack.pop();
+            if(root.right != null && !stack.isEmpty() && root.right == stack.peek()){
+                stack.pop();
+                stack.push(root);
+                root = root.right;
+            } else {
+                vis.visit(root.getValue());
+                root = null;
+            }
+        } while(!stack.isEmpty());
     }
 
     public void levelorder(Visitor<T> vis){
-        List<TreeNode<T>> nodes = new ArrayList<>();
-        nodes.add(root);
-    }
-
-    public void levelorderRec(Visitor<T> vis, List<TreeNode<T>> nodes){
-        List<TreeNode<T>> newNodes = new ArrayList<>();
-        for (TreeNode<T> node : nodes){
-            if(node.right != null){
-                newNodes.add(node.right);
-            }
-            if(node.left != null) {
-                newNodes.add(node.left);
-            }
+        Queue<TreeNode<T>> queue =  new LinkedList<TreeNode<T>>();
+        queue.add(root);
+        while(!queue.isEmpty()){
+            TreeNode<T> node = queue.poll();
             vis.visit(node.getValue());
-        }
-        if(newNodes.size() > 0){
-            levelorderRec(vis, newNodes);
-        }
+            if(node.left != null){
+                queue.add(node.left);
+            }
+            if(node.right != null){
+                queue.add(node.right);
+            }
 
+        }
     }
+
 }