←Back

Merge K Sorted Lists

Hard

Description

You are given an array of k linked-lists, each linked-list is sorted in ascending order. Merge all the linked-lists into one sorted linked-list and return it. This is a classic hard problem that tests your understanding of heaps, divide and conquer, and linked list manipulation.

Examples

Example 1:
Input: 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:
Input: lists = []
Output: []
Example 3:
Input: lists = [[]]
Output: []

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
Linked ListDivide and ConquerHeapMerge Sort
solution.jsJavaScript (Node.js)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

Console

Test Results
▶️

Run your code to see results