/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode partition(ListNode head, int x) {
        ListNode min = new ListNode(0);
        ListNode max = new ListNode(0);
        ListNode tmp2 = min;
        ListNode tmp1 = max;
        
        while (head != null) {
            if (head.val >= x) {
                tmp1.next = head;
                head = head.next;
                tmp1 = tmp1.next;
                tmp1.next = null;
            } else {
                tmp2.next = head;
                head = head.next;
                tmp2 = tmp2.next;
                tmp2.next = null;
            }
        }
        tmp2.next = max.next;
        return min.next;
    }
}