题解 | #【模板】链表#

#include<iostream>
using namespace std;

class List{
private:
    struct ListNode{
    int val;
    ListNode* next;
    ListNode(int n):val(n),next(NULL){}
    };
    ListNode* head=NULL;
public:
    List(){}
    void m_insert(int x,int y){
        ListNode* res=new ListNode(0);
        res->next=head;
        ListNode* pre=res;
        ListNode* cur=head;
        while(cur!=NULL){
            if(cur->val==x){
                ListNode* newnode=new ListNode(y);
                newnode->next=cur;
                pre->next=newnode;
                break;
            }
            pre=cur;
            cur=cur->next;
        }
        if(cur==NULL){
            ListNode* newnode=new ListNode(y);
            newnode->next=cur;
            pre->next=newnode;
        }
        head=res->next;//更新头节点
        free(res);
    }
    void m_delete(int x){
        ListNode* res=new ListNode(0);
        res->next=head;
        ListNode* pre=res;
        ListNode* cur=head;
        while(cur!=NULL){
            if(cur->val==x){
               pre->next=cur->next;
            }
            pre=cur;
            cur=cur->next;
        }
        head=res->next;
        free(res);
    }
    void print(){
        ListNode* cur=head;
        while(cur!=NULL){
            cout<<cur->val<<' ';
            cur=cur->next;
        }
    }
};
int main(){
    int n;
    cin>>n;
    string str;
    List li;
    for(int i=0;i<n;i++){
        cin>>str;
        int x,y;
        if(str=="insert"){
            cin>>x>>y;
            li.m_insert(x,y);
        }
        if(str=="delete"){
            cin>>x;
            li.m_delete(x);
        }
    }
    li.print();
}