Describe a fast recursive algorithm for reversing a singly linked list L, sothat the ordering of the nodes becomes opposite of what it was before. Code and describe each code.

Write a recursive function treeToList(Node root) that takesan ordered binary tree and rearranges the internal pointers to make a circular doubly linked list outof the tree nodes. The "previous" pointers should be stored in the "small" field and the "next"pointers should be stored in the "large" field. The list should be arranged so that the nodes are inincreasing order. Return the head pointer to the new list. The operation can be done in O(n) time -- essentially operating on each node once. Try the problem directly, or see the hints below.Hint #1 The recursion is key. Trust that the recursive call on each sub-tree works and concentrate onassembling the outputs of the recursive calls to build the result. It's too complex to delve into howeach recursive call is going to work -- trust that it did work and assemble the answer from there.Hint #2The recursion will go down the tree, recursively changing the small and large sub-trees into lists,and then append those lists together with the…

3. The following is a recursive algorithm for a preorder binary tree traversal. Determine the worst-case runtime of this algorithm where the proper binary tree t has n internal nodes (non null nodes). Do this by specify the recurrence equation for the runtime T(n) and then deriving the closed form. Count the comparison v != null as 1 primary operation and the call processNode(t,v) as c primary operations, where c is some constant. Algorithm preorder(Tree t, TreeNode v) Input: Binary tree t of size n and node v of t Output: None if v!= null then end end processNode(t.v) preorder(t,v.getLeft()) preorder(t,v.getRight())