【剑指offer】删除链表中重复的结点

public class  {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}

public ListNode deleteDuplication(ListNode pHead) {
    if (pHead == null)
        return null;

    ListNode current = pHead;
    ListNode prev = null;

    while (current != null && current.next != null) {
        if (current.next.val > current.val) {
            prev = current;
            current = current.next;
        }
        else {
            while (current.next != null && current.next.val == current.val)
                current = current.next;

            current = current.next;

            if (prev != null)
                prev.next = current;
            else
                pHead = current;
        }
    }

    return pHead;
}