[LeetCode] Root Equals Sum of Children

1.문제

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.

root , 왼쪽 자식 , 오른쪽 자식으로 이루어진 노드가 3개인 이진트리가 주어질 때 부모 노드값 = 왼쪽 자식노드값 + 오른쪽 자식 노드 값 인지 판별하는 문제이다.

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

2.풀이

1. 부모노드값과 자식노드 값들의 합을 비교하면 된다.

/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {TreeNode} root
 * @return {boolean}
 */
const checkTree = function (root) {
  return root.val === root.left.val + root.right.val;
};

3.결과