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 (Python):

from collections import defaultdict,deque
from heapq import heappush, heappop
import sys
import math
import bisect
import random
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def I(): return int(sys.stdin.readline())
def LS():return [list(x) for x in sys.stdin.readline().split()]
def S():
    res = list(sys.stdin.readline())
    if res[-1] == "\n":
        return res[:-1]
    return res
def IR(n):
    return [I() for i in range(n)]
def LIR(n):
    return [LI() for i in range(n)]
def SR(n):
    return [S() for i in range(n)]
def LSR(n):
    return [LS() for i in range(n)]

sys.setrecursionlimit(1000000)
mod = 1000000007

def solve():
    n = I()
    s = S()
    m = n>>1
    if s[:m] == s[m:]:
        print("Yes")
    else:
        print("No")
    return


if __name__ == "__main__":
    solve()

Solution (Python):
n = int(input())
s = input()
if n%2==0 and s[:n//2] == s[n//2:]:
    print("Yes")
else:
    print("No")

Solution (Python):
N = int(input())
S = input()
T = S[:N // 2]
if S == T + T:
    print('Yes')
else:
    print('No')

Solution (Python):
n = int(input())
s = str(input())
if s[:n//2] == s[n//2:]:
    print("Yes")
else:
    print("No")

Solution (Python):
N=int(input())
s=input()
print("Yes" if s[0:N//2] == s[N//2:] else "No")

Solution (Python):
n = int(input())
s = input()
if n % 2 != 0:
    print('No')
    exit()
if s[:n//2]==s[n//2:]:
    print('Yes')
else:
    print('No')

Solution (Python):
import bisect
import heapq
import itertools
import math
import operator
import os
import re
import string
import sys
from collections import Counter, deque, defaultdict
from copy import deepcopy
from decimal import Decimal
from fractions import gcd
from functools import lru_cache, reduce
from operator import itemgetter, mul, add, xor

import numpy as np

if os.getenv("LOCAL"):
    sys.stdin = open("_in.txt", "r")

sys.setrecursionlimit(10 ** 9)
INF = float("inf")
IINF = 10 ** 18
MOD = 10 ** 9 + 7



N = int(sys.stdin.readline())
S = sys.stdin.readline().rstrip()

a = S [:N//2] == S[N//2:]
if a:
    print('Yes')
else:
    print('No')