ReverseTree

Reverse the Tree

Solution: reverse by threes similair to reverse linked list in pairs

For 4 6 7 subproblem(last subproblem)

6 is new root

6.left = 4

6.right = 7

Node	Action Taken
6 is new root	newRoot = reverseTree(6) = 6
4 is new left	root.left.left = root
7 is new right	root.left.right = root.right
4.left is assigned later by 2	root.left = null
4.right is assigned	root.right = null