MirrorTree

/*
 Given a Binary Tree, convert it into its mirror.
MirrorTree1            

Examples:

Input:
      1
    /  \
   2    3
Output: 3 1 2
Explanation: The tree is
   1    (mirror)  1
 /  \    =>      /  \
2    3          3    2
The inorder of mirror is 3 1 2
Input:
      10
     /  \
    20   30
   /  \
  40  60
Output: 30 10 60 20 40
Explanation: The tree is
      10               10
    /    \  (mirror) /    \
   20    30    =>   30    20
  /  \                   /   \
 40  60                 60   40
The inroder traversal of mirror is
30 10 60 20 40.
Expected Time Complexity: O(N).
Expected Auxiliary Space: O(Height of the Tree).

Constraints:
1 ≤ Number of nodes ≤ 105
1 ≤ Data of a node ≤ 105


 */
//{ Driver Code Starts
// Initial Template for Java

// Contributed by Sudarshan Sharma
import java.util.LinkedList;
import java.util.Queue;
import java.io.*;
import java.util.*;

class Node {
    int data;
    Node left;
    Node right;
    Node(int data) {
        this.data = data;
        left = null;
        right = null;
    }
}

class GfG {

    static Node buildTree(String str) {

        if (str.length() == 0 || str.charAt(0) == 'N') {
            return null;
        }

        String ip[] = str.split(" ");
        // Create the root of the tree
        Node root = new Node(Integer.parseInt(ip[0]));
        // Push the root to the queue

        Queue<Node> queue = new LinkedList<>();

        queue.add(root);
        // Starting from the second element

        int i = 1;
        while (queue.size() > 0 && i < ip.length) {

            // Get and remove the front of the queue
            Node currNode = queue.peek();
            queue.remove();

            // Get the current node's value from the string
            String currVal = ip[i];

            // If the left child is not null
            if (!currVal.equals("N")) {

                // Create the left child for the current node
                currNode.left = new Node(Integer.parseInt(currVal));
                // Push it to the queue
                queue.add(currNode.left);
            }

            // For the right child
            i++;
            if (i >= ip.length) break;

            currVal = ip[i];

            // If the right child is not null
            if (!currVal.equals("N")) {

                // Create the right child for the current node
                currNode.right = new Node(Integer.parseInt(currVal));

                // Push it to the queue
                queue.add(currNode.right);
            }
            i++;
        }

        return root;
    }
    void inOrder(Node node) {
        if (node == null) {
            return;
        }

        inOrder(node.left);
        System.out.print(node.data + " ");

        inOrder(node.right);
    }

    public static void main(String[] args) throws IOException {
        BufferedReader br =
            new BufferedReader(new InputStreamReader(System.in));

        int t = Integer.parseInt(br.readLine());

        while (t-- > 0) {
            String s = br.readLine();
            Node root = buildTree(s);

            Solution g = new Solution();
            g.mirror(root);
            GfG mt = new GfG();
            mt.inOrder(root);
            System.out.println();
        }
    }
}

// } Driver Code Ends


// User function Template for Java

// function Template for Java

// FUNCTION CODE
/* A Binary Tree node
class Node
{
    int data;
    Node left, right;
   Node(int item)
   {
        data = item;
        left = right = null;
    }
} */

class Solution {
    // Function to convert a binary tree into its mirror tree.
    void mirror(Node node) {
        // Your code here
        Queue<Node> que=new LinkedList<>();
        que.add(node);
        while(!(que.isEmpty())){
            int le=que.size();
            for(int i=1;i<=le;i++){
                Node curr=que.poll();
                Node temp=curr.left;
                curr.left=curr.right;
                curr.right=temp;
                if(curr.left!=null){
                    que.add(curr.left);
                }
                if(curr.right!=null){
                    que.add(curr.right);
                }
            }
        }
    }
}