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 A762 {
      public static void main(String[] args) {
          Scanner in = new Scanner(System.in);
          int n = in.nextInt();
          String[] s = new String[n];
          String ans = "";
          for (int i = 0; i < n; i++) {
              s[i] = in.next();
              if (s[i].length() % 2 != 0) {
                  ans += "NO" + "\n";
              } else {
                  boolean check = false;
                  int l = 0;
                  int r = s[i].length() / 2;
                  int iter = r;
                  for (int j = 0; j < iter; j++) {
                      if (s[i].charAt(l) == s[i].charAt(r)) {
                          check = true;
                          l++;
                          r++;
                      } else {
                          ans += "NO" + "\n";
                          check = false;
                          break;
                      }
                  }
                  if (check) {
                      ans += "Yes" + "\n";
                  }
              }
          }
          System.out.println(ans);
  
      }
  }
  