Buggy python submission (verdict: Runtime Error):
N = int(input())
A = list(map(int, input().split()))
A = sorted(A)[::-1]
memo = [0 for i in range(N)]
memo[0] = N-1
memo[1] = N-1
if N % 2 == 0:
    for i in range(2, N):
        memo[i] = memo[i-2]-2
        if memo[i] != A[i]:
            print(0)
            exit()
else:
    for i in range(2, N-1):
        memo[i] = memo[i-2]-2
        if memo[i] != A[i]:
            print(0)
            exit()


# 最初(N//2)**2にしていた、それぞれの場合の数ではなくなってしまう
print((2**(N // 2))%(10**9+7))

Fixed submission:
N = int(input())
if N == 1:
    print(1)
    exit()
A = list(map(int, input().split()))
A = sorted(A)[::-1]
memo = [0 for i in range(N)]
memo[0] = N-1
memo[1] = N-1
if N % 2 == 0:
    for i in range(2, N):
        memo[i] = memo[i-2]-2
        if memo[i] != A[i]:
            print(0)
            exit()
else:
    for i in range(2, N-1):
        memo[i] = memo[i-2]-2
        if memo[i] != A[i]:
            print(0)
            exit()


# 最初(N//2)**2にしていた、それぞれの場合の数ではなくなってしまう
print((2**(N // 2))%(10**9+7))

Buggy python submission (verdict: Runtime Error):
N = int(input())
A = list(map(int, input().split()))
A = sorted(A)[::-1]
memo = [0 for i in range(N)]
memo[0] = N-1
memo[1] = N-1
if N % 2 == 0:
    for i in range(2, N):
        memo[i] = memo[i-2]-2
        if memo[i] != A[i]:
            print(0)
            exit()
else:
    for i in range(2, N-1):
        memo[i] = memo[i-2]-2
        if memo[i] != A[i]:
            print(0)
            exit()



print((2**(N // 2))%(10**9+7))

Fixed submission:
N = int(input())
if N == 1:
    print(1)
    exit()
A = list(map(int, input().split()))
A = sorted(A)[::-1]
memo = [0 for i in range(N)]
memo[0] = N-1
memo[1] = N-1
if N % 2 == 0:
    for i in range(2, N):
        memo[i] = memo[i-2]-2
        if memo[i] != A[i]:
            print(0)
            exit()
else:
    for i in range(2, N-1):
        memo[i] = memo[i-2]-2
        if memo[i] != A[i]:
            print(0)
            exit()


# 最初(N//2)**2にしていた、それぞれの場合の数ではなくなってしまう
print((2**(N // 2))%(10**9+7))

Buggy python submission (verdict: Runtime Error):
N = int(input())
A = list(map(int, input().split()))
A = sorted(A)[::-1]
memo = [0 for i in range(N)]
memo[0] = N-1
memo[1] = N-1
if N % 2 == 0:
    for i in range(2, N):
        memo[i] = memo[i-2]-2
        if memo[i] != A[i]:
            print(0)
            exit()
else:
    for i in range(2, N-1):
        memo[i] = memo[i-2]-2
        if memo[i] != A[i]:
            print(0)
            exit()



print(((N // 2)**2)%(10**9+7))

Fixed submission:
N = int(input())
if N == 1:
    print(1)
    exit()
A = list(map(int, input().split()))
A = sorted(A)[::-1]
memo = [0 for i in range(N)]
memo[0] = N-1
memo[1] = N-1
if N % 2 == 0:
    for i in range(2, N):
        memo[i] = memo[i-2]-2
        if memo[i] != A[i]:
            print(0)
            exit()
else:
    for i in range(2, N-1):
        memo[i] = memo[i-2]-2
        if memo[i] != A[i]:
            print(0)
            exit()


# 最初(N//2)**2にしていた、それぞれの場合の数ではなくなってしまう
print((2**(N // 2))%(10**9+7))

Buggy python submission (verdict: Runtime Error):
N = int(input())
A = list(map(int, input().split()))
# print(A)
if A.count(0) > 1:
    print(0)
    exit()

A = sorted(A)[::-1]
memo = [0 for i in range(N)]
memo[0] = N-1
memo[1] = N-1
if N % 2 == 0:
    for i in range(2, N):
        memo[i] = memo[i-2]-2
        if memo[i] != A[i]:
            print(0)
            exit()
else:
    for i in range(2, N-1):
        memo[i] = memo[i-2]-2
        if memo[i] != A[i]:
            print(0)
            exit()



print(((N // 2)**2)%(10**9+7))

Fixed submission:
N = int(input())
if N == 1:
    print(1)
    exit()
A = list(map(int, input().split()))
A = sorted(A)[::-1]
memo = [0 for i in range(N)]
memo[0] = N-1
memo[1] = N-1
if N % 2 == 0:
    for i in range(2, N):
        memo[i] = memo[i-2]-2
        if memo[i] != A[i]:
            print(0)
            exit()
else:
    for i in range(2, N-1):
        memo[i] = memo[i-2]-2
        if memo[i] != A[i]:
            print(0)
            exit()


# 最初(N//2)**2にしていた、それぞれの場合の数ではなくなってしまう
print((2**(N // 2))%(10**9+7))