题目：
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.
解析：
开始因为疏忽出现了两次runtime error情况，对于链表的问题一般就是如下情况
1. NULL->next
2. 指针是NULL，还用指针的val，p = NULL，p->val
1 /** 2 * Definition for singly-linked list. 3 * struct ListNode { 4 * int val; 5 * ListNode *next; 6 * ListNode(int x) : val(x), next(NULL) {} 7 * }; 8 */ 9 class Solution { 10 public: 11 ListNode* deleteDuplicates(ListNode* head) { 12 if(head == NULL || head->next == NULL) 13 return head; 14 ListNode *p = head; 15 while(p->next) 16 { 17 if(p->val == p->next->val) 18 p->next = p->next->next; 19 else 20 p = p->next; 21 } 22 return head; 23 } 24 };
Remove Duplicates from Sorted List
原文：http://www.cnblogs.com/raichen/p/4999974.html