LinkedList

You are given the heads of two sorted linked lists list1 and list2.Merge the two lists in a one sorted list. The list should be made by splicing together the nodes of the first two lists. Return the head of the merged linked list.
For example,
Input: list1 = 1 -> 2 -> 4 , list2 = 1 -> 3 -> 4
Output: 1 -> 1 -> 2 -> 3 -> 4 -> 4

Given the head of a singly linked list, reverse the list, and return the reversed list.
For example,
Input: 1 -> 2 -> 3 -> 4 -> 5
Output: 5 -> 4 -> 3 -> 2 -> 1

Given the head of a singly linked list, reverse the list, and return the reversed list.
binary For example,
Input: 1 -> 2 -> 3 -> 4 -> 5
Output: 5 -> 4 -> 3 -> 2 -> 1