求助

字符串做法，调了好几天

已经有些面目全非

#include<iostream>
#include<cstdio>
using namespace std;
string book[1005];
int main()
{
    int n,q,s,flagg=1;;
    string smallest="99999999999";
    string temp,a,b;
    cin>>n>>q;
    for (int i=1;i<=n;i++)
    {
        cin>>book[i];
    }
    for (int i=1;i<=q;i++)
    {
        cin>>s>>temp;
        smallest="99999999999";
        for (int j=1;j<=n;j++)
        {
            a=book[j];
            b=book[j].erase(0,book[j].size()-s);
            if (b==temp)
            {
                if (smallest.size()>a.size())
                {
                    smallest=a;
                    flagg=1;
                    book[j]=a;
                    continue;
                }
                else if(smallest.size()==a.size() && smallest>a)
                {
                    smallest=a;
                    flagg=1;
                    book[j]=a;
                    continue;
                }
                cout<<smallest<<endl;
                flagg=1;
                book[j]=a;
                break;
            }
            else 
            {
                cout<<"-1"<<endl;
                flagg=1;
                book[j]=a;
                break;
            }
        }
    }
    return 0;
}