Symmetrical Tree

Category: Binary Trees

Difficulty: Medium

Description

Write a function that takes in a Binary Tree and returns if that tree is symmetrical. A tree is symmetrical if the left and right subtrees are mirror images of each other.

Each BinaryTree node has an integer value, a left child node, and a right child node. Children nodes can either be BinaryTree nodes themselves or None / null.

Sample Input

tree =    1
       /     \
      2       2
    /   \   /   \
   3     4 4     3
 /   \          /  \
5     6        6    5

Sample Output

True

Optimal Space & Time Complexity

O(n) time | O(h) space - where n is the number of nodes in the tree and h is the height of the tree.