[leetcode] Remove Duplicates from Sorted List II

Remove Duplicates from Sorted List II

#include "iostream"
using namespace std;

/**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==NULL||head->next==NULL) {
            return head;
        }
        
        ListNode *res =new ListNode(0);
        res->next=head;//删除后
        ListNode *q=res;
        
        ListNode *p=head;//待处理
        ListNode *tmp=p;
        
        int number=0;
        
        while (p!=NULL) {
            
            while (p!=NULL&&p->val==tmp->val) {
                number++;
                p=p->next;
            }
            
            if (number==1) {
                q=q->next;
            }
            q->next=p;
            number=0;
            tmp=p;
        }
        
        q=res->next;
        res->next=NULL;
        delete res;
        
        return q;
        
    }
};


int main() {
    ListNode *t=new ListNode(1);
    t->next=new ListNode(2);
    //t->next->next=new ListNode(2);
    cout<<t->val<<endl;
    Solution so;
    ListNode *res= so.deleteDuplicates(t);
    cout<<res->val<<res->next->val<<endl;
    return 0;
}