You need to construct a binary tree from a string consisting of parenthesis and integers.
The whole input represents a binary tree. It contains an integer followed by zero, one or two pairs of parenthesis. The integer represents the root's value and a pair of parenthesis contains a child binary tree with the same structure.
You always start to construct the left child node of the parent first if it exists.
Input: "4(2(3)(1))(6(5))" Output: return the tree root node representing the following tree: 4 / \ 2 6 / \ / 3 1 5
'9'in the input string.