Is Root Equals Sum of Children easy or hard?

Root Equals Sum of Children is classified as an Easy problem. It focuses on understanding binary tree node access and simple arithmetic comparison rather than traversal or advanced algorithms.

Root Equals Sum of Children Python/Java solution

The Python or Java solution reads the values of the root and its children and returns whether root.val equals root.left.val plus root.right.val. The logic is identical across languages and runs in O(1) time and O(1) space.

How to solve Root Equals Sum of Children in O(n)?

An O(n) traversal is unnecessary for this problem because the input tree always contains exactly three nodes. The optimal solution directly checks root.val == root.left.val + root.right.val, which runs in O(1) time and O(1) space.

What is the best approach for Root Equals Sum of Children?

The best approach is direct comparison of the root value with the sum of its two children. Access root.val, root.left.val, and root.right.val, compute the sum of the children, and compare it to the root. The algorithm runs in O(1) time and O(1) space because only three nodes are involved.

Is Root Equals Sum of Children asked at Google/Amazon/Meta?

This problem is categorized as an easy binary tree question and appears in interview practice sets for companies like Amazon and Google. It is commonly used to test familiarity with tree node structures and basic conditional logic.

What data structure is used in Root Equals Sum of Children?

The problem uses a binary tree data structure. Each node contains a value and references to left and right child nodes. The solution simply reads values from these nodes without performing traversal.

What is the time complexity of Root Equals Sum of Children?

The time complexity is O(1). The solution performs a constant number of operations by reading the values of the root and its two children and comparing them. No traversal or iteration over the tree is required.

Description Solution Video 1:42

2236. Root Equals Sum of Children

Easy84.8% acceptance5 companies

You are given the root of a binary tree that consists of exactly 3 nodes: the root, its left child, and its right child.

Return true if the value of the root is equal to the sum of the values of its two children, or false otherwise.

Example 1:

Input: root = [10,4,6]
Output: true
Explanation: The values of the root, its left child, and its right child are 10, 4, and 6, respectively.
10 is equal to 4 + 6, so we return true.

Example 2:

Input: root = [5,3,1]
Output: false
Explanation: The values of the root, its left child, and its right child are 5, 3, and 1, respectively.
5 is not equal to 3 + 1, so we return false.

Constraints:

The tree consists only of the root, its left child, and its right child.
-100 <= Node.val <= 100

Asked at 5 companies

Google Amazon Microsoft Meta Bloomberg

Topics

Binary Tree Tree

1:42

Still stuck?Read 3 approaches, or watch a walkthrough.

Open solution

LanguageLoading editor…

1# Definition for a binary tree node.
2# class TreeNode:
3#     def __init__(self, val=0, left=None, right=None):
4#         self.val = val
5#         self.left = left
6#         self.right = right
7class Solution:
8    def checkTree(self, root: Optional[TreeNode]) -> bool:
9        

Starter codePython 3Spaces: 4

Examples

Case 1Case 2

Input

[10,4,6]

Input

[5,3,1]

Your code is saved on this device.Solution