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.Scanner;
  
  /**
   * Accomplished using the EduTools plugin by JetBrains https://plugins.jetbrains.com/plugin/10081-edutools
   *
   * To modify the template, go to Preferences -> Editor -> File and Code Templates -> Other
   */
  
  public class Main {
     public static void main(String[] args) {
        Scanner input = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int testCases = Integer.parseInt(input.nextLine());
        int testCase = 1;
  
        while (testCase <= testCases && input.hasNext()) {
           String inputStr = input.nextLine();
           int inputStrLen = inputStr.length();
           if (inputStrLen % 2 != 0 || !inputStr.substring(0, inputStrLen / 2).equals(inputStr.substring(inputStrLen / 2))) {
              System.out.println("NO");
           } else {
                 System.out.println("YES");
           }
           testCase++;
        }
     }
  }