删除顺序链表中重复的数 (一) leecode

Given a sorted linked list, delete all duplicates such that each element appear only once.

For example,
Given 1->1->2, return 1->2.
Given 1->1->2->3->3, return 1->2->3.

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
public class Solution {
    public ListNode deleteDuplicates(ListNode head) {
        
        if(head==null) return head;
        if(head.next==null) return head;
    
        ListNode pre=head;//save the pre to delete
        ListNode cur=head.next;
        while(cur!=null)
        {
            if(cur.val==pre.val)
            {
            
                pre.next=cur.next;//删除cur节点
                cur=cur.next; //处理下一个节点
                                 
                
            }
            else
            {
                pre=pre.next;
                cur=cur.next;
                
            }
            
            
        }
        
        return head;
        
        
    }
}