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 C (GCC 5.4.1) (judge verdict: Accepted)

#include<stdio.h>
#include<string.h>
int main()
{
    char ar[1001];
    int a,b,i,c,ar1[52]={0};
    scanf("%d",&b);
    getchar();
    gets(ar);
    a=strlen(ar);
    for(i=0;i<a;i++)
    {
        c=(ar[i]-96);
        ar1[c]++;
    }
    int d=0;
    for(i=1;i<=26;i++)
    {
        if(ar1[i]%2==1)d=1;
    }
    if(d==1)printf("No\n");
    else printf("Yes\n");
    return 0;

}