【Remove Duplicates from Sorted List 】cpp

题目：

第一次刷的时候漏掉了这道题。

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.

代码：

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
            if ( !head ) return head;
            ListNode dummpy(-1);
            dummpy.next = head;
            ListNode* pre = head;
            ListNode* curr = head->next;
            while (curr)
            {
                if ( curr->val!=pre->val )
                {
                    pre = curr;
                    curr = curr->next;
                }
                else
                {
                    pre->next = curr->next;
                    curr = curr->next;
                }
            }
            return dummpy.next;
    }
};

tips:

纠结了一下才AC。原因是第一次写的时候：

pre = curr;
curr = curr->next;