Buggy python submission (verdict: Runtime Error):
n = int(input())
lst = [int(e) for e in input().split(' ')]

lst = sorted(lst)

valid_list = []
if n % 2 == 1:
    # 奇数
    valid_list.append(0)
    for i in range(1, int((n + 1) / 2)):
        valid_list.append(i * 2)
        valid_list.append(i * 2)
    if lst == valid_list:
        print(int(2 ** (((n - 1) / 2)) % 1000000007))
    else:
        print(0)
else:
    for i in range(1, int((n / 2) + 1)):
        valid_list.append((i * 2) - 1)
        valid_list.append((i * 2) - 1)
    if lst == valid_list:
        print(int(2 ** ((n / 2)) % 1000000007))
    else:
        print(0)


Fixed submission:
## 2 * 100000 % 1000000007 の高速計算法がわからずOUT

n = int(input())
lst = [int(e) for e in input().split(' ')]

lst = sorted(lst)
result = 1

valid_list = []
if n % 2 == 1:
    # 奇数
    valid_list.append(0)
    for i in range(1, int((n + 1) / 2)):
        valid_list.append(i * 2)
        valid_list.append(i * 2)
    if lst == valid_list:
        for i in range(int((n - 1) / 2)):
            result = (result * 2) % 1000000007
        print(int(result))
    else:
        print(0)
else:
    for i in range(1, int((n / 2) + 1)):
        valid_list.append((i * 2) - 1)
        valid_list.append((i * 2) - 1)
    if lst == valid_list:
        for i in range(int(n / 2)):
            result = (result * 2) % 1000000007
        print(int(result))
    else:
        print(0)

Buggy python submission (verdict: Runtime Error):
n = int(input())
lst = [int(e) for e in input().split(' ')]

lst = sorted(lst)

valid_list = []
if n % 2 == 1:
    # 奇数
    valid_list.append(0)
    for i in range(1, int((n + 1) / 2)):
        valid_list.append(i * 2)
        valid_list.append(i * 2)
    if lst == valid_list:
        print((2 ** (((n - 1) / 2) / 5) % 1000000007) ** 5 % 1000000007)
    else:
        print(0)
else:
    for i in range(1, int((n / 2) + 1)):
        valid_list.append((i * 2) - 1)
        valid_list.append((i * 2) - 1)
    if lst == valid_list:
        print(int(2 ** ((n / 2) / 5) % 1000000007) ** 5 % 1000000007)
    else:
        print(0)


Fixed submission:
## 2 * 100000 % 1000000007 の高速計算法がわからずOUT

n = int(input())
lst = [int(e) for e in input().split(' ')]

lst = sorted(lst)
result = 1

valid_list = []
if n % 2 == 1:
    # 奇数
    valid_list.append(0)
    for i in range(1, int((n + 1) / 2)):
        valid_list.append(i * 2)
        valid_list.append(i * 2)
    if lst == valid_list:
        for i in range(int((n - 1) / 2)):
            result = (result * 2) % 1000000007
        print(int(result))
    else:
        print(0)
else:
    for i in range(1, int((n / 2) + 1)):
        valid_list.append((i * 2) - 1)
        valid_list.append((i * 2) - 1)
    if lst == valid_list:
        for i in range(int(n / 2)):
            result = (result * 2) % 1000000007
        print(int(result))
    else:
        print(0)

Buggy python submission (verdict: Runtime Error):
n = int(input())
lst = [int(e) for e in input().split(' ')]

lst = sorted(lst)

valid_list = []
if n % 2 == 1:
    # 奇数
    valid_list.append(0)
    for i in range(1, int((n + 1) / 2)):
        valid_list.append(i * 2)
        valid_list.append(i * 2)
    if lst == valid_list:
        print(int(2 ** (((n - 1) / 2)) % 1000000007))
    else:
        print(0)
else:
    for i in range(1, int((n / 2) + 1)):
        valid_list.append((i * 2) - 1)
        valid_list.append((i * 2) - 1)
    if lst == valid_list:
        print(int(2 ** ((n / 2)) % 1000000007))
    else:
        print(0)


Fixed submission:
## 2 * 100000 % 1000000007 の高速計算法がわからずOUT

n = int(input())
lst = [int(e) for e in input().split(' ')]

lst = sorted(lst)
result = 1

valid_list = []
if n % 2 == 1:
    # 奇数
    valid_list.append(0)
    for i in range(1, int((n + 1) / 2)):
        valid_list.append(i * 2)
        valid_list.append(i * 2)
    if lst == valid_list:
        for i in range(int((n - 1) / 2)):
            result = (result * 2) % 1000000007
        print(int(result))
    else:
        print(0)
else:
    for i in range(1, int((n / 2) + 1)):
        valid_list.append((i * 2) - 1)
        valid_list.append((i * 2) - 1)
    if lst == valid_list:
        for i in range(int(n / 2)):
            result = (result * 2) % 1000000007
        print(int(result))
    else:
        print(0)