# Flip Equivalent Binary Trees | Coding Challenge

This is one of the popular coding challenges on the binary tree.

Let’s understand the flip operation first.

For a binary tree, we can define a **flip operation** as follows: choose any node, and swap the left and right child subtrees.

**What are flip equivalent binary trees?**

A binary tree **T1** is *flip equivalent* to a binary tree **T2** if and only if we can make **T1** equal to **T2** after some number of flip operations.

**Problem Statement:** Given the roots of two binary trees `root1`

and `root2`

, return `true`

if the two trees are flip equivalent or `false`

otherwise.

Note: This is one of the competitive coding challenges that was asked to me in the **Teachmint coding interview round**.

The difficulty level is intermediate or medium.

**Explanation with an example:**

Consider below two binary trees.

These two binary trees are flip equivalent as we can get one binary tree from another by flipping nodes 1, 3 and 5.

#### Solution in Python Programming

**Prerequisite:**

**Python Code:**

# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, val=0, left=None, right=None):
# self.val = val
# self.left = left
# self.right = right
class Solution:
def flipEquiv(self, root1: Optional[TreeNode], root2: Optional[TreeNode]) -> bool:
if root1 is None and root2 is None:
return True
elif root1 and root2:
if root1.val == root2.val:
return (
self.flipEquiv(root1.left, root2.left) and
self.flipEquiv(root1.right, root2.right)
) or (
self.flipEquiv(root1.left, root2.right) and
self.flipEquiv(root1.right, root2.left)
)
else:
return False
else:
return False

Hope this code is self-explanatory., If you have any doubts or have a better solution, let’s discuss it in the comment section below.

If you are preparing for a coding interview, you can solve this coding question in any programming language of your choice like C/C++, Java, Python, etc.

I am complete Python Nut, love Linux and vim as an editor. I hold a Master of Computer Science from NIT Trichy. I dabble in C/C++, Java too. I keep sharing my coding knowledge and my own experience on <b>CSEstack.org</b> portal.