Create TreeTraversalDemo.java

Author: joydeep1982

TreeTraversalDemo.java

@@ -0,0 +1,114 @@
+package ds.algo.solution;
+
+import java.util.Stack;
+
+public class TreeTraversalDemo {
+
+	public void inOrder(TreeNode node) {
+		if (node == null) {
+			return;
+		}
+		inOrder(node.left);
+		System.out.println(node);
+		inOrder(node.right);
+	}
+	
+	public void inOrderNonRecursive(TreeNode node) {
+		if (node == null) {
+			return;
+		}
+		Stack<TreeNode> stack = new Stack<>();
+		
+		while (node != null) {
+			stack.add(node);
+			node = node.left;
+		}
+		
+		TreeNode temp;
+		while(!stack.isEmpty()) {
+			temp = stack.pop();
+			System.out.println(temp);
+			
+			if (temp.right != null) {
+				temp = temp.right;
+				while (temp != null) {
+					stack.push(temp);
+					temp = temp.left;
+				}
+			}
+		}
+	}
+	
+	public void preOrder(TreeNode node) {
+		if (node == null) {
+			return;
+		}
+		System.out.println(node);
+		preOrder(node.left);
+		preOrder(node.right);
+	}
+	
+	public void preOrderNonRecursive(TreeNode node) {
+		if (node == null) {
+			return;
+		}
+		Stack<TreeNode> stack = new Stack<>();
+		stack.add(node);
+		TreeNode temp;
+		
+		while(!stack.isEmpty()) {
+			temp = stack.pop();
+			System.out.println(temp);
+			if (temp.right != null)
+				stack.add(temp.right);
+			if (temp.left != null)
+				stack.add(temp.left);
+			
+		}
+	}
+	
+	public void postOrder(TreeNode node) {
+		if (node == null) {
+			return;
+		}
+		postOrder(node.left);
+		postOrder(node.right);
+		System.out.println(node);
+	}
+	
+	public void postOrderNonRecursive(TreeNode node) {
+		if (node == null) {
+			return;
+		}
+	}
+}
+
+class TreeNode {
+	
+	int value;
+	
+	TreeNode left;
+	
+	TreeNode right;
+	
+	TreeNode(int val) {
+		this.value = val;
+		this.left = null;
+		this.right = null;
+	}
+	
+	public TreeNode addLeft(TreeNode n) {
+		this.left = n;
+		return this;
+	}
+	
+	public TreeNode addRight(TreeNode n) {
+		this.right = n;
+		return this;
+	}
+	
+	@Override
+	public String toString() {
+		return String.valueOf(this.value);
+	}
+}