1400A — String Similarity 別解

void solve(){
  ll N;cin>>N;
  string s;cin>>s;
  char c = s[N-1];
  stringstream ss;
  rep(i,N)ss<<c;
  p(ss.str());
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    ll N;cin>>N;

    while(N--)solve();
    
    return 0;
}