https://oj.leetcode.com/problems/partition-list/
http://blog.csdn.net/linhuanmars/article/details/24446871
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode(int x) {
* val = x;
* next = null;
* }
* }
*/
public class Solution {
public ListNode partition(ListNode head, int x) {
if (head == null)
return head;
ListNode dummyhead = new ListNode(0);
dummyhead.next = head;
ListNode pre = dummyhead;
ListNode lastmin = dummyhead;
while (pre.next != null)
{
ListNode node = pre.next;
if (node.val >= x)
{
pre = pre.next;
}
else
{
// Tricky.
if (pre == lastmin)
{
// No change
pre = pre.next;
lastmin = lastmin.next;
}
else
{
// Move node after lastmin;
ListNode next = node.next;
pre.next = next;
ListNode lastminnext = lastmin.next;
node.next = lastmin.next;
lastmin.next = node;
lastmin = node;
}
}
}
return dummyhead.next;
}
}
