Official

A - Echo Editorial by en_translator

For beginners
  • If you are new to learning programming and do not know where to start, please try Problem A "Welcome to AtCoder" from practice contest. There you can find a sample code for each language.
  • Also, if you are not familiar with problems in programming contests, we recommend you to try some problems in "AtCoder Beginners Selection".
  • 「競プロ典型 90 問」(Typical 90 Problems of Competitive Programming) is a collection of typical 90 competitive programming problems; unfortunately, currently the problem statements are all Japanese.
  • 「C++入門 AtCoder Programming Guide for beginners (APG4b)」 is a C++ tutorial for competitive programmers. Sadly, this is only in Japanese too.

One can define a variable that stores the string to be printed, but in the competitive programming, all that required is a correct output, so you can slack off and implement the following:

  • Iterate each character of \(S\) with a for statement and print it twice.

Here, you must be careful not to print unnecessary spaces or newlines.

Sample codes (C++):

#include<bits/stdc++.h>

using namespace std;

int main(){
  int n;
  string s;
  cin >> n >> s;
  for(int i=0;i<n;i++){
    cout << s[i] << s[i];
  }cout << "\n";
  return 0;
}

#include<bits/stdc++.h>

using namespace std;

int main(){
  int n;
  string s;
  cin >> n >> s;
  for(auto &letter : s){
    cout << letter << letter;
  }cout << "\n";
  return 0;
}

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