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Code01_MergeKSortedLists.java
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52 lines (44 loc) · 1.02 KB
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package class06;
import java.util.Comparator;
import java.util.PriorityQueue;
// 测试链接：https://leetcode.com/problems/merge-k-sorted-lists/
public class Code01_MergeKSortedLists {
public static class ListNode {
public int val;
public ListNode next;
}
public static class ListNodeComparator implements Comparator<ListNode> {
@Override
public int compare(ListNode o1, ListNode o2) {
return o1.val - o2.val;
}
}
public static ListNode mergeKLists(ListNode[] lists) {
if (lists == null) {
return null;
}
PriorityQueue<ListNode> heap = new PriorityQueue<>(new ListNodeComparator());
for (int i = 0; i < lists.length; i++) {
if (lists[i] != null) {
heap.add(lists[i]);
}
}
if (heap.isEmpty()) {
return null;
}
ListNode head = heap.poll();
ListNode pre = head;
if (pre.next != null) {
heap.add(pre.next);
}
while (!heap.isEmpty()) {
ListNode cur = heap.poll();
pre.next = cur;
pre = cur;
if (cur.next != null) {
heap.add(cur.next);
}
}
return head;
}
}