Initial data commit

Task/Tree-traversal/Java/tree-traversal-1.java

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+import java.util.*;
+
+public class TreeTraversal {
+
+        static class Node<T> {
+		T value;
+		Node<T> left;
+		Node<T> right;
+
+		Node(T value) {
+			this.value = value;
+		}
+
+		void visit() {
+			System.out.print(this.value + " ");
+		}
+	}
+
+	static enum ORDER {
+		PREORDER, INORDER, POSTORDER, LEVEL
+	}
+
+        static <T> void traverse(Node<T> node, ORDER order) {
+		if (node == null) {
+			return;
+		}
+		switch (order) {
+		case PREORDER:
+			node.visit();
+			traverse(node.left, order);
+			traverse(node.right, order);
+			break;
+		case INORDER:
+			traverse(node.left, order);
+			node.visit();
+			traverse(node.right, order);
+			break;
+		case POSTORDER:
+			traverse(node.left, order);
+			traverse(node.right, order);
+			node.visit();
+			break;
+		case LEVEL:
+			Queue<Node<T>> queue = new LinkedList<>();
+			queue.add(node);
+			while(!queue.isEmpty()){
+				Node<T> next = queue.remove();
+				next.visit();
+				if(next.left!=null)
+					queue.add(next.left);
+				if(next.right!=null)
+					queue.add(next.right);
+			}
+		}
+	}	
+
+	public static void main(String[] args) {
+
+		Node<Integer> one = new Node<Integer>(1);
+		Node<Integer> two = new Node<Integer>(2);
+		Node<Integer> three = new Node<Integer>(3);
+		Node<Integer> four = new Node<Integer>(4);
+		Node<Integer> five = new Node<Integer>(5);
+		Node<Integer> six = new Node<Integer>(6);
+		Node<Integer> seven = new Node<Integer>(7);
+		Node<Integer> eight = new Node<Integer>(8);
+		Node<Integer> nine = new Node<Integer>(9);
+		
+		one.left = two;
+		one.right = three;
+		two.left = four;
+		two.right = five;
+		three.left = six;
+		four.left = seven;
+		six.left = eight;
+		six.right = nine;
+
+		traverse(one, ORDER.PREORDER);
+		System.out.println();
+		traverse(one, ORDER.INORDER);
+		System.out.println();
+		traverse(one, ORDER.POSTORDER);
+		System.out.println();
+		traverse(one, ORDER.LEVEL);
+		
+	}
+}