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.

很简单，用一个变量来保存当前判断的value

/*** 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;int value = head->val;ListNode *current = head->next, *precurrent = head,*del = NULL;while (current){if (value == current->val){del = current;precurrent->next = current->next;current = current->next;delete del;}else{precurrent = current;value = current->val;current = current->next;}}return head;}};