题目：
题解：
class Solution:
def sumNumbers(self, root: TreeNode) -> int:
if not root:
return 0
total = 0
nodeQueue = collections.deque([root])
numQueue = collections.deque([root.val])
while nodeQueue:
node = nodeQueue.popleft()
num = numQueue.popleft()
left, right = node.left, node.right
if not left and not right:
total += num
else:
if left:
nodeQueue.append(left)
numQueue.append(num * 10 + left.val)
if right:
nodeQueue.append(right)
numQueue.append(num * 10 + right.val)
return total
