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>
int main(void){
    int r;
    scanf("%d",&r);
    char str[100];
    scanf("%s",str);
    //printf("%s\n",str);
    int flag = 1;
    for(int i=0;i<r/2;i++){
        if(str[i]!=str[i+r/2]){
            flag = 0;
        }
    }
    if(flag==0||r%2==1){
        printf("No\n");
    }else{
        printf("Yes\n");
    }
    return 0;
}