太唐了，我是傻逼

#include<bits/stdc++.h>
using namespace std;
signed main(){
    string s;
    cin>>s;
    int n=s.size(),m,a,b;
    s=" "+s;
    cin>>m;
    while(m--){
        char c,d;
        cin>>c>>a;
        if(c=='Q'){
            cin>>b;
            int ans=0;
            for(int i=a,j=b;i<=n&&j<=n;++i,++j){
                if(s[i]==s[j]) ++ans;
                else break;
            }
            cout<<ans<<endl;
        }
        else if(c=='R'){
            cin>>d;
            s[a]=d;
        }
        else{
            cin>>d;
            s.insert(a+1,d);
            ++n;
        }
    }
	return 0;
}