[LeetCode] Remove Duplicates from Sorted List

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

This is the simplest question. But how many people can get it right at a try?

/**
 * 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 NULL;
        ListNode *prev = head, *curr = head->next;
        
        while(curr)
        {
            if(curr->val == prev->val)
            {
                prev->next = curr->next;
                delete curr;
            }
            else
            {
                prev = curr;
            }
            curr = curr->next;
        }
        return head;
    }
};