You are given an array of k linked-lists lists, each linked-list is sorted in ascending order.

Merge all the linked-lists into one sorted linked-list and return it.

Example 1:

Input: lists = [[1,4,5],[1,3,4],[2,6]]Output: [1,1,2,3,4,4,5,6]Explanation: The linked-lists are: [ 1->4->5, 1->3->4, 2->6 ]merging them into one sorted list: 1->1->2->3->4->4->5->6

Example 2:

Input: lists = []Output: []

Example 3:

Input: lists = [[]]Output: []

Constraints:

• k == lists.length
• 0