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.util.Scanner;
  
  public class SqString {
      public static void main(String[] args) {
          Scanner sc = new Scanner(System.in);
          int t = sc.nextInt();
          sc.nextLine();
          for (int i = 0; i < t; i++) {
              String s = sc.nextLine();
              if (s.length() % 2 != 0) {
                  System.out.println("NO");
                  continue;
              }
              if (s.length() == 2) {
                  if (s.charAt(0) == s.charAt(1)) {
                      System.out.println("YES");
                  } else {
                      System.out.println("NO");
                  }
                  continue;
              }
              if (s.substring(0, s.length() / 2).equals(s.substring(s.length()/2, s.length()))) {
                  System.out.println("YES");
                  continue;
              } else {
                  System.out.println("NO");
              }
          }
      }
  }
  