题解 | #删除链表中重复的结点#

/*
struct ListNode {
    int val;
    struct ListNode *next;
    ListNode(int x) :
        val(x), next(NULL) {
    }
};
*/
#include <unordered_map>
#include <utility>
class Solution {
public:
    ListNode* deleteDuplication(ListNode* pHead) {
        if(pHead==nullptr)
        {
            return nullptr;
        }
        ListNode* cur = pHead;
        unordered_map<int, int>key;
        
        while(cur!=nullptr)
        {
            key[cur->val]++;
            cur=cur->next;
        }

        ListNode* res = new ListNode(0);
        res->next = pHead;
        cur = res;

        while(cur->next!=nullptr)
        {
            if(key[cur->next->val]!=1)
            {
                cur->next = cur->next->next;
            }
            else {
                cur = cur->next;
            }
        }
        return res->next;


        
    }
};