80pts求调

#include <bits/stdc++.h>

using namespace std;

int main() {
    forward_list<int> l;
    l.push_front(1);
    int q;cin>>q;
    _Fwd_list_iterator<int> it;
    while (q--){
        int op,i,j;
        cin>>op;
        switch (op) {
            case 1:
                cin>>i>>j;
                it = find(l.begin(), l.end(), i);
                l.insert_after(it,j);
                break;
            case 2:
                cin>>i;
                it= find(l.begin(), l.end(),i);
                it++;
                if (it==l.end()){
                    cout<<0<<endl;
                    break;
                }
                cout<<*it<<endl;
                break;
            case 3:
                cin>>i;
                it= find(l.begin(), l.end(),i);
                l.erase_after(it);
                break;
            default:
                cout<<"cefaesrf";
        }
    }
    return 0;
}