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;
}