leetcode_86_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.

public ListNode partition(ListNode head, int x) {
		if(head==null||head.next==null)
			return head;
		ListNode little_start=new ListNode(0),little_end=little_start;
		ListNode big_start=new ListNode(0),big_end=big_start;
		ListNode pListNode=head;
		while(pListNode!=null)
		{
			if(pListNode.val<x)
			{
				little_end.next=pListNode;
				little_end=pListNode;
			}else 
			{
				big_end.next=pListNode;
				big_end=pListNode;
			}
			pListNode=pListNode.next;
		}
		little_start=little_start.next;
		big_start=big_start.next;
		if(little_start!=null)
		{
			big_end.next=null;
			little_end.next=big_start;
			return little_start;
		}
		else
			return big_start;
    }