Search⌘ K
AI Features
Home
Courses
Decode the Coding Interview in Swift: Real-World Examples

Flip Equivalent Binary Trees

Explore how to check if two binary trees are flip equivalent by applying recursive logic to compare child subtrees. This lesson guides you through implementing a function to solve the problem and analyzing the time and space complexity of the approach.

We'll cover the following...

Description

Let’s start by defining what a flip operation for a binary tree is. We can define it as:

“Choosing any node and swapping the right and left child subtrees.”

A binary tree, T, is flip equivalent to another binary tree, S, if we can make T equal to S after some number of flip operations.

Given the roots of two binary trees, root1 and root2, you have to find out whether the trees are flip equivalent to each other or not. The flipEquiv function should return True if the binary trees are equivalent. Otherwise, it will return False.

Example

Let’s look at the example below:

Do it yourself!

Swift
import Swift



func flipEquiv(root1: TreeNode?, root2: TreeNode?) -> Bool {

    // write your code here

    return false

}
Flip equivalent binary tree exercise

Solution

We implement the flipEquiv function using recursion. Like any recursive function, we start by defining the base conditions. We have two base conditions:

  1. If root1 or root2 is nil, they are equivalent if and only if they are both nil.

  2. If root1 and root2 have different values, they aren’t ...