Problem:
Score : 200 points

Problem Statement

Given are a positive integer N and a string S of length N consisting of lowercase English letters.

Determine whether the string is a concatenation of two copies of some string.
That is, determine whether there is a string T such that S = T + T.

Constraints

1 \leq N \leq 100

S consists of lowercase English letters.

|S| = N

Input

Input is given from Standard Input in the following format:

N
S

Output

If S is a concatenation of two copies of some string, print Yes; otherwise, print No.

Sample Input 1

6
abcabc

Sample Output 1

Yes

Let T = abc, and S = T + T.

Sample Input 2

6
abcadc

Sample Output 2

No

Sample Input 3

1
z

Sample Output 3

No

Solution in Java7 (OpenJDK 1.7.0) (judge verdict: Runtime Error)



import java.util.Scanner;

public class Main{

    public static void main(String[] args) {
Scanner sc1=new Scanner(System.in);
Scanner sc2=new Scanner(System.in);
int N=sc1.nextInt(),bandera=0;
String texto=sc2.nextLine();
char superstring[]=new char[N];
for(int i=0;i<texto.length();i++){superstring[i]=texto.charAt(i);}
if(N%2==1){System.out.println("No");}
else{for(int i=0;i<N/2;i++){if(superstring[i]!=superstring[i+N/2]){bandera=1;break;}}
if(bandera==0){System.out.println("Yes");}else{System.out.println("No");}
}
    }
    
}