删除链表中重复的结点

题目描述

在一个排序的链表中，存在重复的结点，请删除该链表中重复的结点，重复的结点不保留，返回链表头指针。 例如，链表1->2->3->3->4->4->5 处理后为 1->2->5

/*
struct ListNode {
    int val;
    struct ListNode *next;
    ListNode(int x) :
        val(x), next(NULL) {
    }
};
*/
class Solution {
public:
    ListNode* deleteDuplication(ListNode* pHead)
    {
        if(!pHead)
            return NULL;
        
        map<int, ListNode*> list;
        map<int, bool> list1;
        
        while(pHead)
        {
            if(list.find(pHead->val) == list.end())
            {
                list[pHead->val] = pHead;
                list1[pHead->val] = true;
            }
            else
            {
                list1[pHead->val] = false;
            }
            pHead = pHead->next;
        }
        
        ListNode *newHead = (ListNode*)malloc(sizeof(ListNode));
        newHead->next = NULL;
        ListNode *move = newHead;
        map<int, bool>::iterator it = list1.begin();
        for(;it!=list1.end();it++)
        {
            if(it->second)
            {
                move->next = list[it->first];
                move = move->next;
            }
        }
        
        move->next = NULL;
        return newHead->next;
    }
};