Given an array of linked list, lists, where each linked list's node values are in ascending order, combine all these linked lists into a single sorted linked list and return the head node of the combined linked list.

The linked list is represented by a sequence of ListNodes, where each node points to the next node in the sequence, or null if it is the last node.

A ListNode has the following interface:

interface ListNode {
  val: number;
  next: ListNode | null;
}

Input

• listA: ListNode: Head node of the first linked list. Examples display each linked list as an array of values within the list
• listB: ListNode: Head node of the second linked list. Examples display each linked list as an array of values within the list

Input: listA = [-3,-1,9,10], listB = [-10,3,4,6,9]
Output: [-10,-3,-1,3,4,6,9,9,10]
Explanation: Combining the sorted lists [-3, -1, 9, 10] and [-10, 3, 4, 6, 9] results in a single sorted list [-10, -3, -1, 3, 4, 6, 9, 9, 10].

Input: listA = [1,2,4], listB = [1,3,4]
Output: [1,1,2,3,4,4]
Explanation: Combining the sorted lists [1, 2, 4] and [1, 3, 4] results in a single sorted list [1, 1, 2, 3, 4, 4].

Input: listA = [], listB = [0]
Output: [0]
Explanation: Combining the empty list [] with the sorted list [0] results in the list [0].

Constraints

• 1 <= Number of nodes <= 50
• -100 <= ListNode.val <= 100