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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.
题意：去掉已排序的链表里重复的元素
思路：
1.遍历链表，用一个变量保存当前链表节点的值
2.如果当前链表节点值与前面的一样，则删除当前链表节点
3.否则用当前节点值更新该变量
复杂度：时间O(n)， 空间O(1)
相关题目：
/**
* 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 *pre = head;
ListNode *cur = head->next;
while(cur){
if(cur->val == pre->val){
//delete current node
pre->next = cur->next;
delete cur;
cur = pre->next;
}else{
//update value
pre = cur;
cur = cur->next;
}
}
return head;
}
};Leetcode 线性表 Remove Duplicates from Sorted List,布布扣,bubuko.com
Leetcode 线性表 Remove Duplicates from Sorted List
原文：http://blog.csdn.net/zhengsenlie/article/details/25776319