# 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   3
Output: 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   1
Output: 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`.```
```# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
def sumNumbers(self, root: TreeNode) -> int:
def getNumbers(root, previous, result):
if not root:
return

current = previous*10 + root.val

if not root.left and not root.right:
result[0] += current

getNumbers(root.left, current, result)
getNumbers(root.right, current, result)

ans = [0]
getNumbers(root, 0, ans)
return ans[0] ```