40分求助

rt，代码如下

#include <iostream>
#include <set>
#include <string>

using namespace std;

set<string> s;
int n,q,QAQ;
string tmp;

bool is(string s1,const string &s2){
    if(s1.length() < s2.length()) return false;
    else if(s1.length() == s2.length()) return s1 == s2;
    else{
        s1.erase(0,s1.length() - s2.length());
        return s1 == s2;
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin >> n >> q;
    while(n--){
        cin >> tmp;
        s.insert(tmp);
    }
    while(q--){
        cin >> QAQ >> tmp;
        for(auto i : s){
            if(is(i,tmp)){
                cout << i << '\n';
                goto aim;
            }
        }
        cout << "-1\n";
        aim:
        continue;
    }

    return 0;
}