Merge Two Sorted Lists

You are given the heads of two sorted linked lists list1 and list2. Merge the two lists into one sorted linked list by splicing together the nodes of the input lists. Return the head of the merged linked list.

Example

Input: list1 = [1,2,4], list2 = [1,3,4] Output: [1,1,2,3,4,4]

Input: list1 = [], list2 = [] Output: []

Input: list1 = [], list2 = [0] Output: [0]

Constraints

• The number of nodes in each list is in the range [0, 50].
• -100 ≤ Node.val ≤ 100
• Both list1 and list2 are sorted in non-decreasing order.