Leetcode23.java

/*
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.
Input: lists = [[1,4,5],[1,3,4],[2,6]]
Output: [1,1,2,3,4,4,5,6]
*/
classSolution {
publicListNodemergeKLists(ListNode[] lists) {
PriorityQueue<ListNode> q=newPriorityQueue<>((a,b)->a.val-b.val);
ListNodecurr=newListNode(0);
ListNodeans=curr;

for(ListNodel:lists){
while(l!=null){
q.offer(l);
l=l.next;
 }
 }

while(!q.isEmpty()){
curr.next=q.poll();
curr=curr.next;
curr.next=null;
 }
returnans.next;
 }
}