Description
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.
Examples
Input:
lists = [[1,4,5],[1,3,4],[2,6]]Output:
[1,1,2,3,4,4,5,6]Explanation:
Merging all three sorted lists into one.
Input:
lists = []Output:
[]Explanation:
Empty input returns empty list.
Input:
lists = [[]]Output:
[]Explanation:
Single empty list returns empty.
Constraints
- •
k == lists.length - •
0 ≤ k ≤ 10⁴ - •
0 ≤ lists[i].length ≤ 500 - •
-10⁴ ≤ lists[i][j] ≤ 10⁴ - •
lists[i] is sorted in ascending order. - •
The sum of lists[i].length will not exceed 10⁴.