40分 求助

#include <bits/stdc++.h>
using namespace std;
int main()
{
    int n;
    string str;
    cin>>n>>str;
    for (int i=1;i<=n;i++)
    {
        string str1;
        int a;
        cin>>a;
        int q,s,c;
        if (a==1)
        {
            cin>>str1;
            str+=str1;
            cout<<str<<endl;
        }
        if (a==2)
        {
            string str2;
            cin>>q>>s;
            for (int j=q;j<=q+s;j++)
            {
                str2+=str[j];
            }
            str=str2;
            cout<<str<<endl;
        }
        if (a==3)
        {
            string str3;
            cin>>c>>str3;
            string strl3="";
            for (int j=0;j<str.length();j++)
            {
                strl3+=str[j];
                if (j==c-1)
                {
                    strl3+=str3;
                }
            }
            str=strl3;
            cout<<str<<endl;
        }
        if (a==4)
        {
            cin>>str1;
            if (str.find(str1)<100)
            {
                cout<<str.find(str1)<<endl;
            }
            else
            {
                cout<<-1<<endl;
            }   
        }
    }
    return 0;
}