合并K个有序链表,并且作为一个有序链表的形式返回。分析并描述它的复杂度。
详见:https://leetcode.com/problems/merge-k-sorted-lists/description/
实现语言:Java
/** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode(int x) { val = x; } * } */ class Solution { public ListNode mergeKLists(ListNode[] lists) { int n=lists.length; if(n==0){ return null; } while(n>1){ int k=(n+1)/2; for(int i=0;i<n/2;++i){ lists[i]=mergeTwoLists(lists[i],lists[i+k]); } n=k; } return lists[0]; } private ListNode mergeTwoLists(ListNode l1,ListNode l2){ if(l1==null&&l2==null){ return null; } if(l1==null){ return l2; } if(l2==null){ return l1; } ListNode head=new ListNode(-1); ListNode cur=head; while(l1!=null&&l2!=null){ if(l1.val<l2.val){ cur.next=l1; l1=l1.next; }else{ cur.next=l2; l2=l2.next; } cur=cur.next; } cur.next=l1!=null?l1:l2; return head.next; } }
参考:https://www.cnblogs.com/grandyang/p/4606710.html