hard

ProblemYou 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: 1234567891011Input: 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: 123Input: lists = []Output: [] Example 3: 123Input: lists = [[]]Output: [ ...