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 Codechef
  {
  	public static void main (String[] args) throws java.lang.Exception
  	{
  		// your code goes here
  	   Scanner sc = new Scanner(System.in);
  	   int T = sc.nextInt();
  	   while(T-- > 0)
  	   {
  	       String s = sc.next();
  	       int l = s.length();
  	       int flag = 0;
  	       if(l % 2 == 0)
  	       {
  	           int i = 0;
  	           int j = l/2;
  	           while(j < s.length())
  	           {
  	               if(s.charAt(i) == s.charAt(j))
  	               {
  	                   i++;
  	                   j++;
  	                   
  	               }
  	               else
  	               {
  	                   System.out.println("NO");
  	                   flag = 1;
  	                   break;
  	               }
  	           }
  	           
  	           
  	       }
  	       else{
  	           System.out.println("NO");
  	           flag = 1;
  	       }
  	       if(flag == 0)
  	       {
  	           System.out.println("YES");
  	       }
  	   }
  	}
  }
  