Invert A Binary Tree

Problem Statement

Invert a binary tree. Here is the leetCode link Invert A Binary Tree

Example:

Input:

     4
   /   \
  2     7
 / \   / \
1   3 6   9

Output:

     4
   /   \
  7     2
 / \   / \
9   6 3   1

Solution

This is not a difficult problem to solve. We write a recursive invertTree function, let’s look at the code.

/**
* Definition for a binary tree node.
* function TreeNode(val) {
*     this.val = val;
*     this.left = this.right = null;
* }
*/
/**
* @param {TreeNode} root
* @return {TreeNode}
*/
var invertTree = function(root) {
    if(!root) return root;
    let right = invertTree(root.right);
    let left = invertTree(root.left);

    root.left = right || null;
    root.right = left || null;

    return root;
};