A ternary tree is like a binary tree, except each node in a ternary tree may have three children: a left child, a middle child, and a right child. Write an analogue of the TreeNode declaration that...

A ternary tree is like a binary tree, except each node in a ternary tree may have three children: a left child, a middle child, and a right child. Write an analogue of the TreeNode declaration that can be used to represent the nodes of a ternary tree.