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.*;
  import java.io.*;
  
  public class A {
      static MyScanner sc;
      static PrintWriter out;
      static {
          sc = new MyScanner();
          out = new PrintWriter(System.out);
      }
      public static void solve() {
          String s = sc.next();
          int n = s.length();
          if(n % 2 == 1) {
              out.println("NO");
              return;
          }
          String a = s.substring(0, n / 2);
          String b = s.substring(n / 2, n);
          if(a.equals(b)) out.println("YES");
          else out.println("NO");
      }
      public static void main(String[] args) {
          int t = sc.nextInt();
          while(t-- > 0)
              solve();
          out.flush();
      }
  }
  
  class MyScanner {
      BufferedReader br;
      StringTokenizer tok;
      MyScanner() {
          try { br = new BufferedReader(new InputStreamReader(System.in)); }
          catch(Exception e) { System.out.println(e); }
          tok = new StringTokenizer("");
      }
      public String next() {
          try {
              while(!tok.hasMoreTokens()) tok = new StringTokenizer(br.readLine());
          }
          catch(Exception e) { System.out.println(e); }
          return tok.nextToken();
      }
      public int nextInt() {
          return Integer.parseInt(next());
      }
      public long nextLong() {
          return Long.parseLong(next());
      }
      public double nextDouble() {
          return Double.parseDouble(next());
      }
  }
  