Coding - Merge K Sorted Lists

Problem Statement

Merge K Sorted Lists

You are given an array of k linked lists lists, where each list is sorted in ascending order. Return the sorted linked list that is the result of merging all of the individual linked lists.

Examples

Example 1:

Input: lists = [[1,4,5],[1,3,4],[2,6]] Output: [1,1,2,3,4,4,5,6] Explanation: The lists are: [ 1->4->5, 1->3->4, 2->6 ] merging them as [1->1->2->3->4->4->5->6]

Example 2:

Input: lists = [] Output: [] Explanation: The list is empty, return an empty list.

Example 3:

Input: lists = [[]] Output: [] Explanation: The list contains only one empty list, return an empty list.

Constraints

• 0 <= k <= 104
• 0 <= n <= 105
• -104 <= Node.val <= 104
• lists.length == k
• 0 <= lists[i].length <= 5 * 104
• lists[i] is sorted in ascending order.

Hints

1. Use a min-heap to efficiently get the smallest element from the lists.
2. Rebuild a new sorted list based on the sorted order of elements.