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.*;
  public class B{
    static Scanner sc;
    public static void solve(){
      char[] s=sc.next().toCharArray();
      int n=s.length;
      int k=n/2;
      if(n%2==1){System.out.println("NO"); return;}
      for(int i=0;i<(s.length)/2;i++){
        if(s[i]!=s[k++]){System.out.println("NO"); return;}
      }
      //Integer a[]=new Integer[n];
      //for(int i=0;i<n;i++) a[i]=sc.nextInt();
      System.out.println("YES");
    }
    public static void main(String args[]){
        sc=new Scanner(System.in);
        int t=sc.nextInt();
        while(t-->0) solve();
    }
  }
  