mirror the binary tree

Author: NirmalSilwal

CodingBlocks Training/Day20/mirrorBinaryTree.java

@@ -0,0 +1,169 @@
+package Lecture20;
+
+import java.util.Scanner;
+
+public class mirrorBinaryTree {
+
+	private class Node {
+		int data;
+		Node left;
+		Node right;
+
+		Node(int data, Node left, Node right) {
+			this.data = data;
+			this.left = left;
+			this.right = right;
+		}
+	}
+
+	private Node root;
+	private int size = 0;
+
+	public mirrorBinaryTree() {
+		Scanner sc = new Scanner(System.in);
+		this.root = takeTreeInput(sc, null, false);
+	}
+
+	private Node takeTreeInput(Scanner sc, Node parent, boolean isLeftorRight) {
+		if (parent == null) {
+			System.out.print("Enter data for root node: ");
+		} else {
+			if (isLeftorRight) {
+				System.out.print("Enter data for left child of " + parent.data + ": ");
+			} else {
+				System.out.print("Enter data for right child of: " + parent.data + ": ");
+
+			}
+		}
+
+		int data = sc.nextInt();
+		Node node = new Node(data, null, null);
+		this.size++;
+
+		boolean choice = false;
+		System.out.print("Do you have left child for " + node.data + " -> true/false: ");
+		choice = sc.nextBoolean();
+		if (choice) {
+			node.left = this.takeTreeInput(sc, node, true);
+		}
+
+		choice = false;
+		System.out.print("Do you have right child for " + node.data + " -> true/false: ");
+		choice = sc.nextBoolean();
+		if (choice) {
+			node.right = this.takeTreeInput(sc, node, false);
+		}
+
+		return node;
+	}
+
+	public void display() {
+		this.display(this.root);
+	}
+
+	private void display(Node node) {
+		if (node.left != null) {
+			System.out.print(node.left.data + " => ");
+		} else {
+			System.out.print("END => ");
+		}
+
+		System.out.print(node.data);
+
+		if (node.right != null) {
+			System.out.print(" <= " + node.right.data);
+		} else {
+			System.out.print(" <= END");
+		}
+		System.out.println();
+
+		if (node.left != null) {
+			this.display(node.left);
+		}
+		if (node.right != null) {
+			this.display(node.right);
+		}
+	}
+
+	public void mirror() {
+		this.mirror(this.root);
+	}
+
+	private void mirror(Node node) {
+		if (node == null) {
+			return;
+		}
+		Node temp = node.left;
+		node.left = node.right;
+		node.right = temp;
+
+		this.mirror(node.left);
+		this.mirror(node.right);
+	}
+
+	public static void main(String[] args) {
+
+		mirrorBinaryTree btree = new mirrorBinaryTree();
+		
+		System.out.println("\n--------------- before mirroring ---------------------\n");
+		btree.display();
+
+		btree.mirror();
+		
+		System.out.println("\n--------------- after mirroring ---------------------\n");
+		btree.display();
+	}
+
+}
+
+
+
+
+/* output:
+Enter data for root node: 50
+Do you have left child for 50 -> true/false: true
+Enter data for left child of 50: 25
+Do you have left child for 25 -> true/false: true
+Enter data for left child of 25: 12
+Do you have left child for 12 -> true/false: false
+Do you have right child for 12 -> true/false: false
+Do you have right child for 25 -> true/false: true
+Enter data for right child of: 25: 68
+Do you have left child for 68 -> true/false: true
+Enter data for left child of 68: 17
+Do you have left child for 17 -> true/false: false
+Do you have right child for 17 -> true/false: false
+Do you have right child for 68 -> true/false: false
+Do you have right child for 50 -> true/false: true
+Enter data for right child of: 50: 75
+Do you have left child for 75 -> true/false: true
+Enter data for left child of 75: 48
+Do you have left child for 48 -> true/false: false
+Do you have right child for 48 -> true/false: false
+Do you have right child for 75 -> true/false: true
+Enter data for right child of: 75: 39
+Do you have left child for 39 -> true/false: false
+Do you have right child for 39 -> true/false: false
+
+--------------- before mirroring ---------------------
+
+25 => 50 <= 75
+12 => 25 <= 68
+END => 12 <= END
+17 => 68 <= END
+END => 17 <= END
+48 => 75 <= 39
+END => 48 <= END
+END => 39 <= END
+
+--------------- after mirroring ---------------------
+
+75 => 50 <= 25
+39 => 75 <= 48
+END => 39 <= END
+END => 48 <= END
+68 => 25 <= 12
+END => 68 <= 17
+END => 17 <= END
+END => 12 <= END
+*/