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.*;
  import java.io.*;
  
  public class A {
  
  	public static void main(String[] args) throws IOException {
  		// TODO Auto-generated method stub
  
  		FastReader fr = new FastReader();
  		PrintWriter out = new PrintWriter(System.out);
  
  		int t = fr.nextInt();
  		
  		for(int test = 0;test < t;test++) {
  			
  			String s = fr.next();
  			
  			String ans = "";
  			
  			String fp = "";
  			String sp = "";
  			
  			if(s.length() % 2 != 0) ans = "NO";
  			
  			else {
  				
  				for(int i = 0;i < (s.length()/2);i++) {
  					
  					fp += s.charAt(i);
  					
  				}
  				
  				for(int i = s.length()/2;i < s.length();i++) {
  					
  					sp += s.charAt(i);
  					
  				}
  				
  				if(fp.equals(sp)) ans = "YES";
  				else ans = "NO";
  				
  			}
  			
  			out.println(ans);
  			
  		}
  		
  		fr.close();
  		out.close();
  
  	}
  
  	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;
  
  		}
  
  		void close() throws IOException {
  
  			br.close();
  
  		}
  
  	}
  
  }
  