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.StringTokenizer;
  
  public class Main {
  
      static Scanner sc;
      static PrintWriter pw;
  
      public static void main(String[] args) throws IOException {
          sc = new Scanner(System.in);
          pw = new PrintWriter(System.out);
          solve();
          pw.close();
      }
  
      public static void solve() throws IOException {
          long l = sc.nextInt();
          for (int i = 0; i < l; i++) {
              String s = sc.next();
              if(s.length()%2 != 0){
                  pw.println("NO");
                  continue;
              }
              int len = s.length()/2;
              if (s.substring(0,len).equals(s.substring(len))){
                  pw.println("YES");
              }else{
                  pw.println("NO");
              }
  
          }
  
      }
  
  
      static class Scanner {
          BufferedReader br;
          StringTokenizer st;
  
          public Scanner(InputStream s) {
              br = new BufferedReader(new InputStreamReader(s));
          }
  
          public Scanner(FileReader f) {
              br = new BufferedReader(f);
          }
  
          public String next() throws IOException {
              while (st == null || !st.hasMoreTokens())
                  st = new StringTokenizer(br.readLine());
              return st.nextToken();
          }
  
          public int nextInt() throws IOException {
              return Integer.parseInt(next());
          }
  
          public long nextLong() throws IOException {
              return Long.parseLong(next());
          }
  
          public double nextDouble() throws IOException {
              return Double.parseDouble(next());
          }
  
          public int[] nextIntArr(int n) throws IOException {
              int[] arr = new int[n];
              for (int i = 0; i < n; i++) {
                  arr[i] = Integer.parseInt(next());
              }
              return arr;
          }
  
      }
  }
  