题解 | #删除有序链表中重复的元素-I#

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 *   public ListNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param head ListNode类
     * @return ListNode类
     */
    public ListNode deleteDuplicates (ListNode head) {
        // write code here
        if (head == null) {
            return null;
        }
        ListNode preHead = head;
        ListNode afterHead = head.next;
        while (afterHead != null ) {
            ListNode currNode = afterHead;
            if (preHead.val != currNode.val) {
                preHead.next = currNode;
                preHead = currNode;
            } else {
                preHead.next = currNode.next;
            }
            afterHead = afterHead.next;
        }
        return head;
    }
}