23. Merge k Sorted Lists

Practice Merge k Sorted Lists for free on NudgeCode: Hard, Linked List pattern. Write it in Python or JavaScript, run the tests in your browser, and ask for a hint when you are stuck.

You are given an array of k linked lists, each sorted in ascending order. Merge them all into one sorted linked list and return its head.

Example

lists = [[1,4,5],[1,3,4],[2,6]]  ->  [1,1,2,3,4,4,5,6]

Constraints

• 0 <= k <= 10^4
• 0 <= length of each list <= 500
• -10^4 <= Node.val <= 10^4
• the total number of nodes is at most 10^4