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.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.util.StringTokenizer;
  
  public class cf1619A {
    
    public static void main(String[] args) {
      FastReader sc = new FastReader();
      int t = sc.nextInt();
  
      while(t-->0) {
        String s = sc.nextLine();
        System.out.println(s.substring(0, s.length()/2).equalsIgnoreCase(s.substring(s.length()/2)) ? "YES" : "NO");
      }
    
    }
    
    static class FastReader {
      BufferedReader br;
      StringTokenizer st;
     
      public FastReader() {
        br = new BufferedReader(new InputStreamReader(System.in));
      }
    
      String next() {
        while (st == null || !st.hasMoreElements()) {
          try {
            st = new StringTokenizer(br.readLine());
          } catch (IOException e) {
            e.printStackTrace();
          }
        }
        return st.nextToken();
      }
      
      int nextInt() { return Integer.parseInt(next()); }
    
      long nextLong() { return Long.parseLong(next()); }
    
      double nextDouble() { return Double.parseDouble(next()); }
    
      String nextLine() {
        String str = "";
        try {
          str = br.readLine();
        } catch (IOException e) {
          e.printStackTrace();
        }
        return str;
      }
    }
  }
  