Buggy python submission (verdict: Runtime Error):
import sys
input=sys.stdin.readline
N=int(input())
A=list(map(int,input().split()))
A.sort()
Devide_N=10**9+7
Rem_2_32_DN=(2**32)%Devide_N

if N%2==1:
  if A[0]!=0 or A[1]==0:
    print(0)

  else:
    del A[0]
    for ch_n in range(1,(N-1)//2+1):
      if A[0]!=ch_n*2 or A[1]!=ch_n*2:
        break
      else:
        del A[0:2]
    else:
      #exp=(N-1)//2
      
      #exp_quotient_32=exp//32
      #exp_rem_32=exp%32
      #Rem_ans_Devide_N=1
      #for _ in range(exp_quotient_32):
      #  Rem_ans_Devide_N=(Rem_ans_Devide_N*Rem_2_32_DN)%Devide_N
        
      #print((Rem_ans_Devide_N*2**(exp_rem_32))%Devide_N)
      sys.exit()
    print(0)

else:
  for ch_n in range(1,N//2+1):
    if A[0]!=ch_n*2-1 or A[1]!=ch_n*2-1:
      break
    else:
      del A[0:2]
  else:
    #exp=N//2
    
    #exp_quotient_32=exp//32
    #exp_rem_32=exp%32
    #Rem_ans_Devide_N=1
    #for _ in range(exp_quotient_32):
    #  Rem_ans_Devide_N=(Rem_ans_Devide_N*Rem_2_32_DN)%Devide_N
      
    #print((Rem_ans_Devide_N*2**(exp_rem_32))%Devide_N)
    sys.exit()
  print(0)




Fixed submission:
import sys
input=sys.stdin.readline
N=int(input())
A=list(map(int,input().split()))
A.sort()
Devide_N=10**9+7
Rem_2_32_DN=(2**32)%Devide_N

if N%2==1:
  if (A[0]!=0 or A[1]==0 if N>2 else A[0]!=0):
    print(0)

  else:
    del A[0]
    for ch_n in range(1,(N-1)//2+1):
      if A[0]!=ch_n*2 or A[1]!=ch_n*2:
        break
      else:
        del A[0:2]
    else:
      exp=(N-1)//2
      
      exp_quotient_32=exp//32
      exp_rem_32=exp%32
      Rem_ans_Devide_N=1
      for _ in range(exp_quotient_32):
        Rem_ans_Devide_N=(Rem_ans_Devide_N*Rem_2_32_DN)%Devide_N
        
      print((Rem_ans_Devide_N*2**(exp_rem_32))%Devide_N)
      sys.exit()
    print(0)

else:
  for ch_n in range(1,N//2+1):
    if A[0]!=ch_n*2-1 or A[1]!=ch_n*2-1:
      break
    else:
      del A[0:2]
  else:
    exp=N//2
    
    exp_quotient_32=exp//32
    exp_rem_32=exp%32
    Rem_ans_Devide_N=1
    for _ in range(exp_quotient_32):
      Rem_ans_Devide_N=(Rem_ans_Devide_N*Rem_2_32_DN)%Devide_N
      
    print((Rem_ans_Devide_N*2**(exp_rem_32))%Devide_N)
    sys.exit()
  print(0)

Buggy python submission (verdict: Runtime Error):
import sys
input=sys.stdin.readline
N=int(input())
A=list(map(int,input().split()))
A.sort()
Devide_N=10**9+7
Rem_2_32_DN=(2**32)%Devide_N

if N%2==1:
  if A[0]!=0 or A[1]==0:
    print(0)

  else:
    del A[0]
    for ch_n in range(1,(N-1)//2+1):
      if A[0]!=ch_n*2 or A[1]!=ch_n*2:
        break
      else:
        del A[0:2]
    else:
      exp=(N-1)//2
      
      exp_quotient_32=exp//32
      exp_rem_32=exp%32
      Rem_ans_Devide_N=1
      for _ in range(exp_quotient_32):
        Rem_ans_Devide_N=(Rem_ans_Devide_N*Rem_2_32_DN)%Devide_N
        
      print((Rem_ans_Devide_N*2**(exp_rem_32))%Devide_N)
      sys.exit()
    print(0)
else:
  for ch_n in range(1,N//2+1):
    if A[0]!=ch_n*2-1 or A[1]!=ch_n*2-1:
      break
    else:
      del A[0:2]
  else:
    exp=N//2
    
    exp_quotient_32=exp//32
    exp_rem_32=exp%32
    Rem_ans_Devide_N=1
    for _ in range(exp_quotient_32):
      Rem_ans_Devide_N=(Rem_ans_Devide_N*Rem_2_32_DN)%Devide_N
      
    print((Rem_ans_Devide_N*2**(exp_rem_32))%Devide_N)
    sys.exit()
  print(0)




Fixed submission:
import sys
input=sys.stdin.readline
N=int(input())
A=list(map(int,input().split()))
A.sort()
Devide_N=10**9+7
Rem_2_32_DN=(2**32)%Devide_N

if N%2==1:
  if (A[0]!=0 or A[1]==0 if N>2 else A[0]!=0):
    print(0)

  else:
    del A[0]
    for ch_n in range(1,(N-1)//2+1):
      if A[0]!=ch_n*2 or A[1]!=ch_n*2:
        break
      else:
        del A[0:2]
    else:
      exp=(N-1)//2
      
      exp_quotient_32=exp//32
      exp_rem_32=exp%32
      Rem_ans_Devide_N=1
      for _ in range(exp_quotient_32):
        Rem_ans_Devide_N=(Rem_ans_Devide_N*Rem_2_32_DN)%Devide_N
        
      print((Rem_ans_Devide_N*2**(exp_rem_32))%Devide_N)
      sys.exit()
    print(0)

else:
  for ch_n in range(1,N//2+1):
    if A[0]!=ch_n*2-1 or A[1]!=ch_n*2-1:
      break
    else:
      del A[0:2]
  else:
    exp=N//2
    
    exp_quotient_32=exp//32
    exp_rem_32=exp%32
    Rem_ans_Devide_N=1
    for _ in range(exp_quotient_32):
      Rem_ans_Devide_N=(Rem_ans_Devide_N*Rem_2_32_DN)%Devide_N
      
    print((Rem_ans_Devide_N*2**(exp_rem_32))%Devide_N)
    sys.exit()
  print(0)

Buggy python submission (verdict: Runtime Error):
import sys
input=sys.stdin.readline
N=int(input())
A=list(map(int,input().split()))

Devide_N=10**9+7
Rem_2_32_DN=(2**32)%Devide_N

if N%2==1:
  if A.count(0)!=1:
    print(0)
  else:
    for ch_n in range(1,(N-1)//2+1):
      if A.count(ch_n*2)!=2:
        break
      else:
        A.remove(ch_n*2)
        A.remove(ch_n*2)
    else:
      #exp=(N-1)//2
      
      #exp_quotient_32=exp//32
      #exp_rem_32=exp%32
      #Rem_ans_Devide_N=1
      #for _ in range(exp_quotient_32):
      #  Rem_ans_Devide_N=(Rem_ans_Devide_N*Rem_2_32_DN)%Devide_N
        
      #print((Rem_ans_Devide_N*2**(exp_rem_32))%Devide_N)
      sys.exit()
    print(0)
else:
  for ch_n in range(1,N//2+1):
    if A.count(ch_n*2-1)!=2:
      break
    else:
      A.remove(ch_n*2-1)
      A.remove(ch_n*2-1)
  else:
    #exp=N//2
    
    #exp_quotient_32=exp//32
    #exp_rem_32=exp%32
    #Rem_ans_Devide_N=1
    #for _ in range(exp_quotient_32):
    #  Rem_ans_Devide_N=(Rem_ans_Devide_N*Rem_2_32_DN)%Devide_N
      
    #print((Rem_ans_Devide_N*2**(exp_rem_32))%Devide_N)
    #sys.exit()
  print(0)




Fixed submission:
import sys
input=sys.stdin.readline
N=int(input())
A=list(map(int,input().split()))
A.sort()
Devide_N=10**9+7
Rem_2_32_DN=(2**32)%Devide_N

if N%2==1:
  if (A[0]!=0 or A[1]==0 if N>2 else A[0]!=0):
    print(0)

  else:
    del A[0]
    for ch_n in range(1,(N-1)//2+1):
      if A[0]!=ch_n*2 or A[1]!=ch_n*2:
        break
      else:
        del A[0:2]
    else:
      exp=(N-1)//2
      
      exp_quotient_32=exp//32
      exp_rem_32=exp%32
      Rem_ans_Devide_N=1
      for _ in range(exp_quotient_32):
        Rem_ans_Devide_N=(Rem_ans_Devide_N*Rem_2_32_DN)%Devide_N
        
      print((Rem_ans_Devide_N*2**(exp_rem_32))%Devide_N)
      sys.exit()
    print(0)

else:
  for ch_n in range(1,N//2+1):
    if A[0]!=ch_n*2-1 or A[1]!=ch_n*2-1:
      break
    else:
      del A[0:2]
  else:
    exp=N//2
    
    exp_quotient_32=exp//32
    exp_rem_32=exp%32
    Rem_ans_Devide_N=1
    for _ in range(exp_quotient_32):
      Rem_ans_Devide_N=(Rem_ans_Devide_N*Rem_2_32_DN)%Devide_N
      
    print((Rem_ans_Devide_N*2**(exp_rem_32))%Devide_N)
    sys.exit()
  print(0)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
input=sys.stdin.readline
N=int(input())
A=list(map(int,input().split()))

Devide_N=10**9+7
Rem_2_32_DN=(2**32)%Devide_N

if N%2==1:
  if A.count(0)!=1:
    print(0)
  else:
    for ch_n in range(1,(N-1)//2+1):
      if A.count(ch_n*2)!=2:
        break
      else:
        A.remove(ch_n*2)
        A.remove(ch_n*2)
    else:
      exp=(N-1)//2
      
      exp_quotient_32=exp//32
      exp_rem_32=exp%32
      Rem_ans_Devide_N=1
      for _ in range(exp_quotient_32):
        Rem_ans_Devide_N=(Rem_ans_Devide_N*Rem_2_32_DN)%Devide_N
        
      print((Rem_ans_Devide_N*2**(exp_rem_32))%Devide_N)
      sys.exit()
    print(0)
else:
  for ch_n in range(1,N//2+1):
    if A.count(ch_n*2-1)!=2:
      break
    else:
      A.remove(ch_n*2-1)
      A.remove(ch_n*2-1)
  else:
    exp=N//2
    
    exp_quotient_32=exp//32
    exp_rem_32=exp%32
    Rem_ans_Devide_N=1
    for _ in range(exp_quotient_32):
      Rem_ans_Devide_N=(Rem_ans_Devide_N*Rem_2_32_DN)%Devide_N
      
    print((Rem_ans_Devide_N*2**(exp_rem_32))%Devide_N)
    sys.exit()
  print(0)

Fixed submission:
import sys
input=sys.stdin.readline
N=int(input())
A=list(map(int,input().split()))
A.sort()
Devide_N=10**9+7
Rem_2_32_DN=(2**32)%Devide_N

if N%2==1:
  if (A[0]!=0 or A[1]==0 if N>2 else A[0]!=0):
    print(0)

  else:
    del A[0]
    for ch_n in range(1,(N-1)//2+1):
      if A[0]!=ch_n*2 or A[1]!=ch_n*2:
        break
      else:
        del A[0:2]
    else:
      exp=(N-1)//2
      
      exp_quotient_32=exp//32
      exp_rem_32=exp%32
      Rem_ans_Devide_N=1
      for _ in range(exp_quotient_32):
        Rem_ans_Devide_N=(Rem_ans_Devide_N*Rem_2_32_DN)%Devide_N
        
      print((Rem_ans_Devide_N*2**(exp_rem_32))%Devide_N)
      sys.exit()
    print(0)

else:
  for ch_n in range(1,N//2+1):
    if A[0]!=ch_n*2-1 or A[1]!=ch_n*2-1:
      break
    else:
      del A[0:2]
  else:
    exp=N//2
    
    exp_quotient_32=exp//32
    exp_rem_32=exp%32
    Rem_ans_Devide_N=1
    for _ in range(exp_quotient_32):
      Rem_ans_Devide_N=(Rem_ans_Devide_N*Rem_2_32_DN)%Devide_N
      
    print((Rem_ans_Devide_N*2**(exp_rem_32))%Devide_N)
    sys.exit()
  print(0)