Given the root node of a binary tree where each node contains a digit from 0 to 9, compute the sum of all numbers formed by root-to-leaf paths. Each path forms a number by concatenating the digits from the root to the leaf. Return the total sum of all such numbers.
Example 1
Input: TreeNode(8, TreeNode(3, TreeNode(2), TreeNode(7)), TreeNode(5))
Output: 832+837+85=1754
Explanation: Paths: 8->3->2 (832), 8->3->7 (837), 8->5 (85). Sum = 832+837+85=1754.
Example 2
Input: TreeNode(6, TreeNode(1), TreeNode(4, None, TreeNode(9)))
Output: 61+649=710
Explanation: Paths: 6->1 (61), 6->4->9 (649). Sum = 61+649=710.
Constraints
Case 1
Input: TreeNode(2, TreeNode(0, None, TreeNode(3)), TreeNode(1))
Expected: 203+21=224
Case 2
Input: TreeNode(9, TreeNode(5, TreeNode(1)), TreeNode(6, None, TreeNode(2)))
Expected: 951+962=1913
Case 3
Input: TreeNode(4, TreeNode(7), None)
Expected: 47
Case 4
Input: TreeNode(1, None, TreeNode(2, TreeNode(3), None))
Expected: 123