Buggy python submission (verdict: Runtime Error):

n = int(input())
a = list(map(int,input().split()))

if n%2==0:
    if sorted(a) != [(k//2)*2+1 for k in range(n)]:
        print(0)
    else:
        print(int(2**(n//2) % (10e9+7)))
else:
    if sorted(a)!= [0]+[(k//2+1)*2 for k in range(n-1)]:
        print(0)
    else:
        print(int(2**(n//2) % (10e9+7)))

Fixed submission:
n = int(input()) 
a = list(map(int,input().split())) 
sa = sorted(a) 

if n % 2 == 0:
  k = 1
  l = 0
else:
  k = 0
  l = 1 

a=1000000007
flag = True 
for i,s in enumerate(sa):
  if ((i+l)//2)*2+k != s:
    flag = False
if flag:
  print(2**(n//2) % a)
else:
  print(0)

Buggy python submission (verdict: Runtime Error):
n = int(input()) 
a = list(map(int,input().split())) 
sa = sorted(a) 

if n % 2 == 0:
  k = 1
  l = 0
else:
  k = 0
  l = 1 

a=1000000007
lag = True 
for i,s in enumerate(sa):
  if ((i+l)//2)*2+k != s:
    flag = False
if flag:
  print(2**(n//2) % a)
else:
  print(0) 

Fixed submission:
n = int(input()) 
a = list(map(int,input().split())) 
sa = sorted(a) 

if n % 2 == 0:
  k = 1
  l = 0
else:
  k = 0
  l = 1 

a=1000000007
flag = True 
for i,s in enumerate(sa):
  if ((i+l)//2)*2+k != s:
    flag = False
if flag:
  print(2**(n//2) % a)
else:
  print(0)

Buggy python submission (verdict: Runtime Error):
n = int(intput())

a = list(map(int,input().split()))

sa = sorted(a)

if n % 2 == 0:
  k = 0
else:
  k = 1

flag = True

for i,s in enumerate(sa):
  if (i/2)*2+k != s:
    flag = False

if flag:
  print(2**n/2)
else:
  print(0)


Fixed submission:
n = int(input()) 
a = list(map(int,input().split())) 
sa = sorted(a) 

if n % 2 == 0:
  k = 1
  l = 0
else:
  k = 0
  l = 1 

a=1000000007
flag = True 
for i,s in enumerate(sa):
  if ((i+l)//2)*2+k != s:
    flag = False
if flag:
  print(2**(n//2) % a)
else:
  print(0)

Buggy python submission (verdict: Runtime Error):
n = int(intput())

a = list(map(int,input().split()))

sa = sorted(a)

if n % 2 == 0:
  k = 0
else:
  k = 1

flag = True

for i,s in enumerate(sa):
  if (i/2)*2+k != s:
    flag = false

if flag:
  print(2**n/2)
else:
  print(0)


Fixed submission:
n = int(input()) 
a = list(map(int,input().split())) 
sa = sorted(a) 

if n % 2 == 0:
  k = 1
  l = 0
else:
  k = 0
  l = 1 

a=1000000007
flag = True 
for i,s in enumerate(sa):
  if ((i+l)//2)*2+k != s:
    flag = False
if flag:
  print(2**(n//2) % a)
else:
  print(0)

Buggy python submission (verdict: Runtime Error):
n = int(intput())

a = list(map(int,input().split()))

sa = sorted(a)

if n % 2 == 0:
  k = 0
else:
  k = 1

flag = True

for i,s in enumerate(sa):
  if (i//2)*2+k != s:
    flag = false

if flag:
  print(2**n//2)
else:
  print(0)


Fixed submission:
n = int(input()) 
a = list(map(int,input().split())) 
sa = sorted(a) 

if n % 2 == 0:
  k = 1
  l = 0
else:
  k = 0
  l = 1 

a=1000000007
flag = True 
for i,s in enumerate(sa):
  if ((i+l)//2)*2+k != s:
    flag = False
if flag:
  print(2**(n//2) % a)
else:
  print(0)

Buggy python submission (verdict: Runtime Error):
n = int(intput())

a = list(map(int,input().split()))

sa = sorted(a)

if n % 2 == 0;
  k = 0
else;
  k = 1

flag = True

for i,s in enumerate(sa);
  if (i//2)*2+k != s;
    flag = false

if flag;
  print(2**n//2)
else;
  print(0)


Fixed submission:
n = int(input()) 
a = list(map(int,input().split())) 
sa = sorted(a) 

if n % 2 == 0:
  k = 1
  l = 0
else:
  k = 0
  l = 1 

a=1000000007
flag = True 
for i,s in enumerate(sa):
  if ((i+l)//2)*2+k != s:
    flag = False
if flag:
  print(2**(n//2) % a)
else:
  print(0)