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.io.*;
  			import java.util.*;
  			import java.lang.*;
  
  			public final class A{
  			public static void main (String[] args)throws IOException{
  					
  					//taking input using BufferedReader class
  					BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
  					
  					//taking total count of testcases
  					int t = Integer.parseInt(br.readLine());
  			        while(t-->0){
  			            String s1=br.readLine();
  			            String s2="";
  			            String s3="";
  			            if(s1.length()%2!=0)
  			            {
  			            System.out.println("NO");
  			            continue;
  			            }
  			            else{
  			                for(int i=0;i<s1.length()/2;i++)
  			                {
  			                char ch=s1.charAt(i);
  			                s2=s2+ch;
  			                }
  			              for(int i=s1.length()/2;i<s1.length();i++)
  			                {
  			                 char ch=s1.charAt(i);
  			                 s3=s3+ch;
  			                 }
  			                if(s2.equals(s3))
  			                System.out.println("YES");  else
  			                System.out.println("NO");
  			               }
  			            
  			          
  			            }
  			    }
  
  			    
  			}