Merge k Sorted Lists
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
[1] -> [4] -> [5] -> null [1] -> [3] -> [4] -> null [2] -> [6] -> null --- [1] -> [1] -> [2] -> [3] -> [4] -> [4] -> [5] -> [6] -> null
Input
lists = [[1,4,5],[1,3,4],[2,6]]Output
[1,1,2,3,4,4,5,6]Merging the three sorted linked lists produces one sorted list containing all values.
Example 2
null --- null
Input
lists = []Output
[]There are no linked lists to merge, so the result is an empty list.
Constraints
- k == lists.length
- 0 <= k <= 10^4
- 0 <= lists[i].length <= 500
- -10^4 <= lists[i][j] <= 10^4
- lists[i] is sorted in ascending order.
- The sum of lists[i].length will not exceed 10^4.