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.InputStreamReader;
  import java.io.PrintWriter;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.StringTokenizer;
  
  public class ProblemA {
  	public static void solution() {
  		//TODO
  	}
  	
  	public static void main(String[] args) throws Exception {
  		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
  		PrintWriter writer = new PrintWriter(System.out);
  		
  		int tt = Integer.parseInt(reader.readLine()); // One number per line
  		
  		for (int t = 0; t < tt; t++) {
  			String s = reader.readLine();
  			if (s.length() % 2 == 1) {
  				writer.println("NO");
  			}
  			else {
  				char[] arr = new char[s.length()];
  				for (int i = 0; i < arr.length; i++) {
  					arr[i] = s.charAt(i);
  				}
  				boolean found = false;
  				for (int i = 0; i < arr.length / 2; i++) {
  					if (arr[i] != arr[i + arr.length / 2]) {
  						writer.println("NO");
  						found = true;
  						break;
  					}
  				}
  				if (!found) {
  					writer.println("YES");
  				}
  			}
  			//StringTokenizer info = new StringTokenizer(reader.readLine()); // Multiple numbers per line
  			//Integer.parseInt(info.nextToken()); // For next number
  		}
  		
  		
  		reader.close();
  		writer.close();
  	}
  }
  