1- import java .util .*;
1+ import java .util .Arrays ;
2+ import java .util .Comparator ;
3+ import java .util .PriorityQueue ;
24
5+ /**
6+ * @author Arun Pandey (https://github.com/pandeyarun709)
7+ */
38public class Merge_K_SortedLinkedlist {
4-
5- /*
6- * This function merge K sorted LinkedList
7- * @param Node []a : array of LinkedList
8- * @param int N : size of array
9- *
10- * author Arun Pandey (https://github.com/pandeyarun709)
11- */
12- Node mergeKList (Node []a ,int N )
13- {
9+
10+ /**
11+ * This function merge K sorted LinkedList
12+ *
13+ * @param a array of LinkedList
14+ * @param N size of array
15+ * @return node
16+ */
17+ Node mergeKList (Node []a ,int N ) {
1418// Min Heap
15- PriorityQueue <Node >min =new PriorityQueue <>(new Comparator <Node >(){
16-
17- public int compare (Node x ,Node y ){
18- return x .data -y .data ;
19- }
20- });
21-
19+ PriorityQueue <Node >min =new PriorityQueue <>(Comparator .comparingInt (x ->x .data ));
20+
2221// adding head of all linkedList in min heap
23- for (int i =0 ;i <N ;i ++)
24- {
25- min .add (a [i ]);
26- }
27-
22+ min .addAll (Arrays .asList (a ).subList (0 ,N ));
23+
2824// Make new head among smallest heads in K linkedList
2925Node head =min .poll ();
3026min .add (head .next );
3127Node curr =head ;
3228
33- //merging LinkedList
34- while (!min .isEmpty ()) {
35-
29+ //
30+ while min .isEmpty ()) {
31+
3632Node temp =min .poll ();
3733curr .next =temp ;
3834curr =temp ;
39-
40- //Add Node in min Heap only if temp.next is not null
41- if (temp .next !=null ){
35+
36+ //
37+ if temp .next !=null )
4238min .add (temp .next );
4339 }
4440 }
45-
46- return head ;
47-
48-
49- }
50-
51- // Node Class
52- private class Node {
53- private int data ;
54- private Node next ;
55-
56- public Node (int d )
57- {
58- this .data =d ;
59- next =null ;
60- }
41+
42+ return head ;
6143 }
6244
63- }
45+ private class Node {
46+ private int data ;
47+ private Node next ;
48+
49+ public Node (int d ) {
50+ this .data =d ;
51+ next =null ;
52+ }
53+ }
54+ }