牛客题目链接

1. 题目考点

1. 使用哑结点
2. 链表节点删除

2. 考点解析

public ListNode deleteDuplicates (ListNode head) {
    // write code here
    if (head == null) return null;
    
    ListNode newHead = new ListNode(0);
    newHead.next = head;
    ListNode p = head, pre = newHead;
    
    while (p != null && p.next != null) {
    	// 关键：找到重复元素的起点
        if (p.val == p.next.val) {
            ListNode temp = p.next;
            while (temp != null && temp.val == p.val) {
                temp = temp.next;
            }
            pre.next = temp;
            p = temp;
        } else {
            pre = p;
            p = p.next;
        }
    }
    return newHead.next;
}