description: A string is called square if it is some string written twice in a row. For example, the strings "aa", "abcabc", "abab" and "baabaa" are square. But the strings "aaa", "abaaab" and "abcdabc" are not square.
  
  For a given string s determine if it is square.
  
  Input
  
  The first line of input data contains an integer t (1 ≤ t ≤ 100) —the number of test cases.
  
  This is followed by t lines, each containing a description of one test case. The given strings consist only of lowercase Latin letters and have lengths between 1 and 100 inclusive.
  
  Output
  
  For each test case, output on a separate line:
  
    * YES if the string in the corresponding test case is square, 
    * NO otherwise. 
  
  
  
  You can output YES and NO in any case (for example, strings yEs, yes, Yes and YES will be recognized as a positive response).
  
  Example
  
  Input
  
  
  10
  a
  aa
  aaa
  aaaa
  abab
  abcabc
  abacaba
  xxyy
  xyyx
  xyxy
  
  
  Output
  
  
  NO
  YES
  NO
  YES
  YES
  YES
  NO
  NO
  NO
  YES
solution: import java.io.BufferedReader;
  import java.io.InputStreamReader;
  import java.util.concurrent.ExecutionException;
  
  public class A  {
      public static void main(String[] args) throws Exception {
          BufferedReader b = new BufferedReader(new InputStreamReader(System.in));
          int t = Integer.parseInt(b.readLine());
          while (t -->0){
              String str = b.readLine();
              String st1 = str.substring(0 ,str.length()/2);
              String st2 = str.substring(str.length()/2,str.length());
              if(st1.equals(st2))System.out.println("YES");
              else System.out.println("NO");
  
  
          }
      }
  }
  