Java for LintCode 链表插入排序

    public ListNode insertionSortList(ListNode head) {
		ListNode root = new ListNode(Integer.MIN_VALUE);
		while (head != null) {
			ListNode temp = root;
			while (temp.next != null && head.val >= temp.next.val)
				temp = temp.next;
			if(temp.next==null){
				temp.next=head;
				head=head.next;
				temp.next.next=null;
			}
			else{
				ListNode temp2 = temp.next;
				temp.next=head;
				head=head.next;
				temp.next.next=temp2;
			}
		}
		return root.next;
    }