### 129.Sum Root to Leaf Numbers

Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number.

An example is the root-to-leaf path 1->2->3 which represents the number 123.

Find the total sum of all root-to-leaf numbers.

Note: A leaf is a node with no children.

Example:

Input: [1,2,3]    1   / \  2   3Output: 25

Explanation:

The root-to-leaf path 1->2 represents the number 12. The root-to-leaf path 1->3 represents the number 13. Therefore, sum = 12 + 13 = 25.

Example 2:

Input: [4,9,0,5,1]    4   / \  9   0 / \5   1Output: 1026
Explanation:
The root-to-leaf path 4->9->5 represents the number 495.The root-to-leaf path 4->9->1 represents the number 491.The root-to-leaf path 4->0 represents the number 40.Therefore, sum = 495 + 491 + 40 = 1026.

### Analyze

/** * Definition for a binary tree node. * function TreeNode(val) { *     this.val = val; *     this.left = this.right = null; * } *//** * @param {TreeNode} root * @return {number} */var sumNumbers = function(root) {  const analyzeObj = { sum: 0 }  if (!root) return analyzeObj.sum
analyzeSum(root, '', analyzeObj)  return analyzeObj.sum};
var analyzeSum = function(node, str, analyzeObj) {  if (!node) return  if (!node.left && !node.right) {    str += String(node.val)    analyzeObj.sum = analyzeObj.sum + parseInt(str, 10)    return  }
str += String(node.val)
analyzeSum(node.left, str, analyzeObj)  analyzeSum(node.right, str, analyzeObj)}

113、257