1class Node{
2    constructor(val){
3        this.val = val;
4        this.left  = null;
5        this.right = null;
6    }
7}
8
9const one = new Node(1);
10const two = new Node(2);
11const three = new Node(3);
12
13three.right = two
14three.left = one
15
16
17const ten = new Node(10);
18const twenty = new Node(20);
19const thirty = new Node(30);
20const tenLeft = new Node(10);
21const tenRight = new Node(10);
22
23
24ten.right = thirty
25ten.left = twenty
26twenty.right = tenRight
27twenty.left = tenLeft
28
29
30class Solution {
31    isSumTree(node){
32        if(!node) return 1;
33        if(!node.left && !node.right) return 1;
34        let result = this.sumCheckerHelper(node)
35        return result.isSumTree
36    }
37
38    sumCheckerHelper(node){
39        if(!node) return {sum : 0, isSumTree: 1};
40        if(!node.left && !node.right) return {sum : node.val, isSumTree: 1};
41        let left = this.sumCheckerHelper(node.left)
42        let right = this.sumCheckerHelper(node.right)
43        let totalSum = left.sum + right.sum + node.val
44        let isSumTree = left.isSumTree && right.isSumTree && (node.val === right.sum + left.sum)
45        return {sum : totalSum, isSumTree : isSumTree}
46    }
47}
48const solution = new Solution();
49console.log(solution.isSumTree(three));
50console.log(solution.isSumTree(ten));