LeetCode Partition List

Given a linked list and a value x, partition it such that all nodes less than x come before nodes greater than or equal to x.

You should preserve the original relative order of the nodes in each of the two partitions.

For example,
Given 1->4->3->2->5->2 and x = 3,
return 1->2->2->4->3->5.

 

 1 /**
 2  * Definition for singly-linked list.
 3  * public class ListNode {
 4  *     int val;
 5  *     ListNode next;
 6  *     ListNode(int x) {
 7  *         val = x;
 8  *         next = null;
 9  *     }
10  * }
11  */
12 public class Solution {
13     public ListNode partition(ListNode head, int x) {
14         if (head==null) return head;
15         ListNode less,greater,l,g;
16         ListNode curr=head;
17         less=new ListNode(-1);
18         greater=new ListNode(1);
19         l=less;
20         g=greater;
21         while (curr!=null){
22             if (curr.val<x){
23                 less.next=curr;
24                 less=less.next;
25             }else {
26                 greater.next = curr;
27                 greater=greater.next;
28             }
29             curr=curr.next;
30         }
31         less.next=g.next;
32         greater.next=null;
33         return l.next;
34         
35     }
36 }

 

posted @ 2014-11-06 12:28  birdhack  阅读(108)  评论(0)  编辑  收藏  举报