Write a function combineWith that could be added to the Set…
Write a function combineWith that could be added to the Set class from lecture. The function accepts a reference to another binary tree of integers as a parameter and combines the two trees into a new third tree which is returned. The new tree’s structure should be a union of the structures of the two original trees; it should have a node in any location where there was a node in either of the original trees (or both). The nodes of the new tree should store an integer indicating which of the original trees had a node at that position (1 if just the first tree had the node, 2 if just the second tree had the node, 3 if both trees had the node). For example, suppose Set variables t1 and t2 have been initialized and store the following trees: t1 t2 +—+ | 9 | +—+ / \ / \ +—+ +—+ | 6 | | 14| +—+ +—+ / \ \ / \ \ +—+ +—+ +—+ | 9 | | 2 | | 11| +—+ +—+ +—+ / / +—+ | 4 | +—+ +—+ | 0 | +—+ / \ / \ +—+ +—+ | -3| | 8 | +—+ +—+ / / \ / / \ +—+ +—+ +—+ | 8 | | 5 | | 6 | +—+ +—+ +—+ \ \ +—+ | 1 | +—+ Then the following call: Set t3 = t1.combineWith(t2); will return the following tree: t3 +—+ | 3 | +—+ / \ / \ +—+ +—+ | 3 | | 3 | +—+ +—+ / \ / \ / \ / \ +—+ +—+ +—+ +—+ | 3 | | 1 | | 2 | | 3 | +—+ +—+ +—+ +—+ / \ / \ +—+ +—+ | 1 | | 2 | +—+ +—+ You are writing a public function for a binary tree class defined as follows: struct TreeNode { int data; // data stored in this node TreeNode* left; // reference to left subtree TreeNode* right; // reference to right subtree }; class Set { private: TreeNode* overallRoot; public: }; You are writing a function that will become part of the Set class from lecture. You may define private helper functions to solve this problem, but otherwise you may not call any other functions of the class. You may not construct any extra data structures to solve this problem. Remember that you can access the member variables of any Set, including a passed in one or newly created one, from inside the Set class.