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: /* package codechef; // don't place package name! */
  
  import java.util.*;
  import java.lang.*;
  import java.io.*;
  
  /* Name of the class has to be "Main" only if the class is public. */
  public class Main
  {
   
    public static void main (String[] args) throws java.lang.Exception
    {
      // your code goes here
      InputStreamReader r = new InputStreamReader(System.in);
      BufferedReader br = new BufferedReader(r);
      int t = Integer.parseInt(br.readLine());
      while (t-- > 0) {
        String s = br.readLine();
        int n = s.length();
        if(n%2 != 0){
            System.out.println("NO");
        }else{
            boolean flag = true;
            for(int i=0; i<n/2; i++){
                if(s.charAt(i) != s.charAt(n/2+i)){
                    flag = false;
                    break;
                }
            }
            if(flag){
                System.out.println("YES");
            }else{
                System.out.println("NO");
            }
        }
  
      }
    }
  }