MirrorBinaryTree.java

// Mirror Binary Tree
// Send Feedback
// For a given Binary Tree of type integer, update it with its corresponding
// mirror image.
// Example:
// Alt text

// Input Format:
// The first and the only line of input will contain the node data, all
// separated by a single space. Since -1 is used as an indication whether the
// left or right node data exist for root, it will not be a part of the node
// data.
// Output Format:
// The only line of output prints the mirrored tree in a level-wise order.
// Each level will be printed on a new line. Elements printed at each level will
// be separated by a single line.
// Note:
// You are not required to print anything explicitly. It has already been taken
// care of.
// Constraints:
// 1 <= N <= 10^5
// Where N is the total number of nodes in the binary tree.

// Time Limit: 1 sec
// Sample Input 1:
// 1 2 3 4 5 6 7 -1 -1 -1 -1 -1 -1 -1 -1
// Sample Output 1:
// 1
// 3 2
// 7 6 5 4
// Sample Input 2:
// 5 10 6 2 3 -1 -1 -1 -1 -1 9 -1 -1
// Sample Output 2:
// 5
// 6 10
// 3 2
// 9

// Following is the structure used to represent the Binary Tree Node

class BinaryTreeNode<T> {
    T data;
    BinaryTreeNode<T> left;
    BinaryTreeNode<T> right;

    public BinaryTreeNode(T data) {
        this.data = data;
        this.left = null;
        this.right = null;
    }
}

class Solution {

    public static void mirrorBinaryTree(BinaryTreeNode<Integer> root) {
        // Your code goes here
        if (root == null) {
            return;
        }
        if (root.left != null && root.right != null) {
            BinaryTreeNode<Integer> temp = root.right;
            root.right = root.left;
            root.left = temp;
        }

        mirrorBinaryTree(root.left);
        mirrorBinaryTree(root.right);
    }

}