题解 | #【模板】链表#

#include <bits/stdc++.h>
using namespace std;

int main() 
{
    list<int> mylist;
    int n;
    cin>>n;
    for(int i=0;i<n;i++)
    {
        string s;
        cin>>s;
        if(s=="insert")
        {
            int x,y;
            cin>>x>>y;
            if(mylist.empty())
                mylist.push_back(y);
            else
            {
                auto it=mylist.begin();
                for(;it!=mylist.end();it++)
                {
                    if(*it==x)
                    {
                        mylist.insert(it,y);
                        break;//及时跳出循环
                    }
                }
                if(it==mylist.end())
                    mylist.push_back(y);
            }
        }
        else
        {
            int x;
            cin>>x;
            auto it=mylist.begin();
            for(;it!=mylist.end();it++)
            {
                if(*it==x)
                {
                    mylist.erase(it);
                    break;//及时跳出循环
                }    
            }
        }
    }
    if(mylist.empty())
        cout<<"NULL";
    else
    {
        for(auto it=mylist.begin();it!=mylist.end();it++)
        {
            cout<<*it<<" ";
        }
    }
    return 0;
}