TnT/Multi_CodeNet4Repair huggingface dataset:
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
from collections import Counter


N = int(input())
lstA = list(map(int, input().split()))
mod = 10**9 + 7
countA = Counter(lstA)
ans = 0

if N % 2:
    if countA[0] == 1 and all(countA[i] == 2 for i in range(2, N, 2)):
        ans = pow(2, N//2) // mod
else:
    if all(countA[i] == 2 for i in range(1, N, 2)):
        ans = pow(2, N//2) // mod


print(ans)


from collections import Counter


N = int(input())
lstA = list(map(int, input().split()))
mod = 10**9 + 7
countA = Counter(lstA)
ans = 0

if N % 2:
    if countA[0] == 1 and all(countA[i] == 2 for i in range(2, N, 2)):
        ans = 2**(N//2) % mod
else:
    if all(countA[i] == 2 for i in range(1, N, 2)):
        ans = 2**(N//2) % mod


print(ans)


Verdicts: Wrong Answer

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
n = int(input())
a = list(map(int, input().split()))
a.sort()
b = True
for i,j in enumerate(a):
  if n % 2:
    if j != ((i+1) // 2) * 2:
      b = False
      break
  else:
    if j != (i // 2) * 2 + 1:
      b = False
      break
if b == True:
  print(((n // 2) ** 2) % mod)
else:
  print(0)

n = int(input())
a = list(map(int, input().split()))
a.sort()
b = True
mod = 10 ** 9 + 7
for i,j in enumerate(a):
  if n % 2:
    if j != ((i+1) // 2) * 2:
      b = False
      break
  else:
    if j != (i // 2) * 2 + 1:
      b = False
      break
if b == True:
  print(pow(2,n//2,mod))
else:
  print(0)


Verdicts: Runtime Error

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
from collections import Counter
def powmod(a,n,m): #a^n mod m
    ans=1
    while n!=0:
        if n&1: ans*=a
        a**=2
        n>>=1
    return ans
n=int(input())
a=list(map(int,input().split()))
a.sort()
dic=Counter(a)
if n%2==0:
    temp={}
    for i in range(1,n,2):
        temp[i]=2
    if temp!=dict(dic):
        print(0)
        exit()
else:
    temp={}
    temp[0]=1
    for i in range(0,n,2):
        temp[i]=2
    if temp!=dict(dic):
        print(0)
        exit()
print(powmod(2,n//2,10**9+7))

from collections import Counter

def powmod(a,n,m): #a^n mod m
    ans=1
    while n!=0:
        if n&1: ans=ans*a%m
        a=a*a%m
        n>>=1
    return ans%m

n=int(input())
a=list(map(int,input().split()))
a.sort()
dic=Counter(a)
if n%2==0:
    temp={}
    for i in range(1,n,2):
        temp[i]=2
    if temp!=dict(dic):
        print(0)
        exit()
else:
    temp={}
    temp[0]=1
    for i in range(2,n,2):
        temp[i]=2
    if temp!=dict(dic):
        print(0)
        exit()
print(powmod(2,n//2,10**9+7))

Verdicts: Wrong Answer

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
n=int(input())
a=list(map(int,input().split()))
mod=10**9+7
d=dict()
for i in range(n):
  if a[i] not in d:
    d[a[i]]=1
  else:
    d[a[i]]+=1
d=sorted(list(d.items()))
if n%2:
  for i in range(len(d)):
    if i==0:
      if d[i][0]!=0 or d[i][1]!=1:
        print(0)
        exit()
    else:
      if d[i][0]!=i*2 or d[i][1]!=2:
        print(0)
        exit()
  print(pow(2,len(d)-1,mod)
else:
  for i in range(len(d)):
    if d[i][0]!=2*i+1 or d[i][1]!=2:
      print(0)
      exit()
  print(2,len(d),mod)

n=int(input())
a=list(map(int,input().split()))
mod=10**9+7
d=dict()
for i in range(n):
  if a[i] not in d:
    d[a[i]]=1
  else:
    d[a[i]]+=1
d=sorted(list(d.items()))
if n%2:
  for i in range(len(d)):
    if i==0:
      if d[i][0]!=0 or d[i][1]!=1:
        print(0)
        exit()
    else:
      if d[i][0]!=i*2 or d[i][1]!=2:
        print(0)
        exit()
  print(pow(2,len(d)-1,mod))
else:
  for i in range(len(d)):
    if d[i][0]!=2*i+1 or d[i][1]!=2:
      print(0)
      exit()
  print(pow(2,len(d),mod))

Verdicts: Runtime Error

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
import sys
from collections import defaultdict

read = sys.stdin.read
readline = sys.stdin.buffer.readline
sys.setrecursionlimit(10 ** 8)
INF = float('inf')
MOD = 10 ** 9 + 7


def main():
    N = int(readline())
    A = list(map(int, readline().split()))
    A.sort()
    if N % 2 == 0:
        for i in range(0, N, 2):
            if A[i] == A[i + 1] == i + 1:
                continue
            else:
                print(0)
                sys.exit()
    else:
        for i in range(1, N, 2):
            if A[i] == A[i + 1] == i + 1:
                continue
            else:
                print(0)
                sys.exit()
        if A[0] != 0:
            print(0)
            sys.exit()
    print(pow(2, (N + 1) // 2, MOD))


if __name__ == '__main__':
    main()


import sys
from collections import defaultdict

read = sys.stdin.read
readline = sys.stdin.buffer.readline
sys.setrecursionlimit(10 ** 8)
INF = float('inf')
MOD = 10 ** 9 + 7


def main():
    N = int(readline())
    A = list(map(int, readline().split()))
    A.sort()
    if N % 2 == 0:
        for i in range(0, N, 2):
            if A[i] == A[i + 1] == i + 1:
                continue
            else:
                print(0)
                sys.exit()
    else:
        for i in range(1, N, 2):
            if A[i] == A[i + 1] == i + 1:
                continue
            else:
                print(0)
                sys.exit()
        if A[0] != 0:
            print(0)
            sys.exit()
    print(pow(2, N // 2, MOD))


if __name__ == '__main__':
    main()


Verdicts: Wrong Answer

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
from collections import defaultdict,Counter
n = int(input())
al = list(map(int, input().split()))

c_al  = Counter(al)

if n % 2 == 0 and 0 not in c_al.values():
    print(int(2**(n/2))%(10**9) + 7)
elif n % 2 != 0 and c_al[0] == 1:
    print(int(2 ** (n // 2))%(10**9) + 7)
else:
    print(0)

from collections import Counter

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

c_al = Counter(al)
print(c_al)
mod = int(10**9 + 7)

if n % 2 == 0:
    for k,v in c_al.items():
        if v != 2:
            print(0)
            exit()
    print((2 ** (n / 2)) % mod)
elif n % 2 != 0:
    for k, v in c_al.items():
        if k == 0:
            if v != 1:
                print(0)
                exit()
        elif v != 2:
            print(0)
            exit()
    print((2 ** (n // 2)) % mod)

from collections import Counter

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

c_al = Counter(al)

if n % 2 == 0:
    for k,v in c_al.items():
        if v != 2:
            print(0)
            exit()
    print(pow(2, n // 2, 10 ** 9 + 7))

elif n % 2 != 0:
    for k, v in c_al.items():
        if k == 0:
            if v != 1:
                print(0)
                exit()
        elif v != 2:
            print(0)
            exit()
    print(pow(2, n // 2, 10 ** 9 + 7))

Verdicts: Runtime Error

Runtime Error

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
n=int(input())
a=list(map(int,input().split()))
a.sort()

if a[0]==0:
    a.remove(0)
    sta=0
else:
    sta=1
for i in range(1,len(a),2):
    if a[i]!=a[i-1] or a[i]%2!=sta or a[i]!=2*(i+1)-sta:
        print(0)
        exit()
ans=2**(len(a)//2)
print(ans)

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

if a[0]==0:
    a.remove(0)
    sta=0
else:
    sta=1
for i in range(1,len(a),2):
    if a[i]!=a[i-1] or a[i]%2!=sta or a[i]!=i+1-sta:
        print(0)
        exit()
ans=2**(len(a)//2)
print(ans%(10**9+7))

Verdicts: Wrong Answer

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
def main():
    import sys

    def input(): return sys.stdin.readline().rstrip()

    n = int(input())
    mod = 10**9 + 7
    a.sort()
    check = [i+1 - (i+n)%2 for i in range(n)]
    if a != check:
        print(0)
        return
    else:
        ans = pow(2, n//2, mod)
        print(ans)




if __name__ == '__main__':
    main()

def main():
    import sys

    def input(): return sys.stdin.readline().rstrip()

    n = int(input())
    a = map(int, input().split())
    mod = 10**9 + 7
    a.sort()
    check = [i+1 - (i+n)%2 for i in range(n)]
    if a != check:
        print(0)
        return
    else:
        ans = pow(2, n//2, mod)
        print(ans)




if __name__ == '__main__':
    main()

def main():
    import sys

    def input(): return sys.stdin.readline().rstrip()

    n = int(input())
    a = list(map(int, input().split()))
    mod = 10**9 + 7
    a.sort()
    check = [i+1 - (i+n)%2 for i in range(n)]
    if a != check:
        print(0)
        return
    else:
        ans = pow(2, n//2, mod)
        print(ans)




if __name__ == '__main__':
    main()

Verdicts: Runtime Error

Runtime Error

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
from collections import Counter
mod = 10 ** 9 + 7
ans = 0
n = int(input())
A = list(map(int, input().split()))
c = Counter(A).most_common()
val, cnt = zip(*c)
val = sorted(list(val))
cnt = sorted(list(cnt))
if n % 2 == 0:
    if cnt == [2] * (n // 2) and val == [i for i in range(n) if i % 2 != 0]:
        ans = (n // 2) ** 2
else:
    if cnt.count(0) == 1 and cnt == [1] + [2] * (n // 2) and val == [i for i in range(n) if i % 2 == 0]:
        ans = (n // 2) ** 2
print(ans % mod)


from collections import Counter
mod = 10 ** 9 + 7
ans = 0
n = int(input())
A = list(map(int, input().split()))
c = Counter(A)
flag = True
if n % 2 == 0:
    odd = 1
    for val, cnt in sorted(c.items()):
        # print(val, cnt)
        if cnt == 2 and val == odd:
            odd += 2
        else:
            flag = False
            break
else:
    even = 0
    for val, cnt in sorted(c.items()):
        # print(val, cnt)
        if val == 0 and cnt == 1:
            even += 2
            continue
        if val == even and cnt == 2:
            even += 2
            continue
        else:
            flag = False
            break
if flag:
    ans = pow(2, n // 2, mod)
else:
    ans = 0
print(ans)


Verdicts: Wrong Answer

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
N = int(input())
A = map(int, input().split())

if N%2 == 0:
    count = [(2 if i%2 == 1 else 0) for i in range(N)]
else:
    count = [(2 if i%2 == 0 else 0) for i in range(N)]
    count[0] = 1

for a in A:
    count[a] -= 1
    if count[a] < 0:
        print(0)
        break
else:
    print(2**(N//2)/(10**9+7))

N = int(input())
A = map(int, input().split())

if N%2 == 0:
    count = [(2 if i%2 == 1 else 0) for i in range(N)]
else:
    count = [(2 if i%2 == 0 else 0) for i in range(N)]
    count[0] = 1

for a in A:
    count[a] -= 1
    if count[a] < 0:
        print(0)
        break
else:
    print(2**(N//2)%(10**9+7))

Verdicts: Wrong Answer

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
n = int(input())
a = sorted(list(map(int, input().split())))
if n % 2 == 1:
    for i in range(0, n, 2):
        if i == 0 and a[i] != 0:
            print(0)
            exit()
        elif a[i] != a[i + 1] or a[i] != 2 * i:
            print(0)
            exit()
else:
    for i in range(0, n, 2):
        if a[i] != a[i + 1] or a[i] != 2 * i + 1:
            print(0)
            exit()
print(2 ** (n // 2))

n = int(input())
a = sorted(list(map(int, input().split())))
if n % 2 == 1 and a[0] != 0:
    print(0)
    exit()
for i in range(n % 2, n, 2):
    if a[i] != a[i + 1] or a[i] != i + 1:
        print(0)
        exit()
print(2 ** (n // 2) % (10 ** 9 + 7))

Verdicts: Runtime Error

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
import collections
N=int(input())
A=list(map(int,input().split()))
if N%2==1:
    if 0 not in A:
        print(0)
    else:
        B=A.remove(0)
        Bc=dict(collections.Counter(B))
        for i in Bc.keys():
            if Bc[i]!=2:
                print(0)
                break
        else:
            print(2**(B//2)%(10**9+7))
else:
    Bc=dict(collections.Counter(A))
    for i in Bc.keys():
        if Bc[i]!=2:
            print(0)
            break
    else:
        print(2**(B//2)%(10**9+7))            

import collections
N=int(input())
A=list(map(int,input().split()))
if N%2==1:
    if 0 not in A:
        print(0)
    else:
        A.remove(0)
        Bc=dict(collections.Counter(A))
        for i in Bc.keys():
            if Bc[i]!=2:
                print(0)
                break
        else:
            print((2**(len(A)//2))%(10**9+7))
else:
    Bc=dict(collections.Counter(A))
    for i in Bc.keys():
        if Bc[i]!=2:
            print(0)
            break
    else:
        print((2**(len(A)//2))%(10**9+7))            

Verdicts: Runtime Error

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
import sys
n = int(input())
a = list(map(int, input().split(' ')))

a.sort()
if n%2 == 0:
    for i in range(n-1):
        if i%2 == 0:
            if a[i] == a[i+1]:
                continue
            else:
                print(0)
                sys.exit()
        else:
            if a[i]+2 == a[i+1]:
                continue
            else:
                print(0)
                sys.exit()
    print((2 ** (n//2)) % (10**9+7))
else:
    if a[0] == 0:
        for i in range(1, n-1):
            if i%2 == 1:
                if a[i] == a[i+1]:
                    continue
                else:
                    print(0)
                    sys.exit()
            else:
                if a[i]+2 == a[i+1]:
                    continue
                else:
                    print(0)
                    sys.exit()
        print(2**((n-1)/2)%(10**9+7))
    else:
        print(0)
        sys.exit()

def main():
    import sys
    n = int(input())
    a = list(map(int, input().split(' ')))
    if n%2 == 1:
        a.append(0)
    a.sort()
    for i in range(n-1):
        if i%2 == 0:
            if a[i] == a[i+1]:
                continue
            else:
                print(0)
                sys.exit()
        else:
            if a[i]+2 == a[i+1]:
                continue
            else:
                print(0)
                sys.exit()
    result = 2 ** (n//2)
    print(result % (10**9+7))
if __name__ == '__main__':
    main()

Verdicts: Runtime Error

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
n = int(input())
lst = [int(e) for e in input().split(' ')]

lst = sorted(lst)

valid_list = []
if n % 2 == 1:
    
    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)




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

lst = sorted(lst)
result = 1

valid_list = []
if n % 2 == 1:
    
    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)


Verdicts: Runtime Error

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
N = int(input())
A = [int(i) for i in input().split()]
count = [0 for _ in range(N+1)]

if N % 2 == 0:
    if len(set(A)) != int(N/2):
        print(0)
        exit()
else:
    if len(set(A)) != int(N/2)+1:
        print(0)
        exit()

for i in A:
    count[i] += 1

res = 1
for i in range(N+1):
    if count[i] == 2:
        res *= 2
    else:
        if i != 0 and N%2 != 0:
            print(0)
            exit()

print(res % (10**9+7))

N = int(input())
A = [int(i) for i in input().split()]
count = [0 for _ in range(N+1)]

if N % 2 == 0:
    if len(set(A)) != int(N/2):
        print(0)
        exit()
else:
    if len(set(A)) != int(N/2)+1:
        print(0)
        exit()

for i in A:
    count[i] += 1

res = 1
for i in range(N+1):
    if count[i] == 2:
        res *= 2
    else:
        if i != 0 and N%2 != 0:
            print(0)
            exit()

print(res)

N = int(input())
A = [int(i) for i in input().split()]
count = [0 for _ in range(N+1)]

if N % 2 == 0:
    if len(set(A)) != int(N/2):
        print(0)
        exit()
else:
    if len(set(A)) != int(N/2)+1:
        print(0)
        exit()

for i in A:
    count[i] += 1

#print(count)

res = 1
for i in range(N+1):
    if count[i] == 2:
        res *= 2
    else:
        if count[i] != 0:
            if N % 2 == 1 and i != 0: 
                print(0)
                exit()

print(res % (10**9+7))

Verdicts: Wrong Answer

Wrong Answer

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
n=int(input())
a=list(map(int,input().split()))

b=[0 for _ in range(n)]
for i in range(n):
    b[a[i]]+=1
print(b)
c= 1 if n%2==0 else 0

if n%2==1:
  if b[0]!=1:
    print(0)
  else:
    for i in range(2,n,2):
      if b[i]!=2:
        print(0)
        break
    else:
      print(2**(n//2))
else:
  for i in range(1,n,2):
    if b[i]!=2:
      print(0)
      break
    else:
      print(2**(n//2))    


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

b=[0 for _ in range((n+1)//2)]
for i in range(n):
    b[a[i]//2]+=1
if n%2==0:
  for i in range(n//2):
    if b[i]!=2:
      print(0)
      break
  else:
    print(pow(2,n//2,10**9+7))
else:
  if b[0]!=1:
    print(0)
  else:
    for i in range(1,n//2+1):
      if b[i]!=2:
        print(0)
        break
    else:
      print(pow(2,n//2,10**9+7))    


Verdicts: Wrong Answer

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
N=int(input())
A=list(map(int,input().split()))
if N%2==0:
	for i in range (N):
		A[i]%2!=1:
			print(0)
			exit()
	print((2**N)%(10**9+7))
else:
	for i in range (N):
		A[i]%2!=0:
			print(0)
			exit()
	if min(A)!=0:
		print(0)
		exit()
	else:
		print((2**(N-1))%(10**9+7))

N=int(input())
A=list(map(int,input().split()))
if N%2==0:
	for i in range (N):
		if A[i]%2 != 1:
			print(0)
			exit()
	print((2**(N//2))%(10**9+7))
else:
	for i in range (N):
		if A[i]%2!=0:
			print(0)
			exit()
	if min(A)!=0 or A.count(0)!=1:
		print(0)
		exit()
	else:
		print((2**((N-1)//2))%(10**9+7))

Verdicts: Runtime Error

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
mod = 10**9+7

n = int(input())
a = sorted(f())
if n&1:
    if all([a[i] == i+i%2 for i in range(n)]):
        print(1<<((n-1)//2)%mod)
    else:
        print(0)
else:
    if all([a[i] == i+(i+1)%2 for i in range(n)]):
        print(1<<(n//2)%mod)
    else:
        print(0)

f = lambda: list(map(int,input().split()))
mod = 10**9+7

n = int(input())
a = sorted(f())
if n&1:
    if all([a[i] == i+i%2 for i in range(n)]):
        print(2**(n//2)%mod)
    else:
        print(0)
else:
    if all([a[i] == i+(i+1)%2 for i in range(n)]):
        print(2**(n//2)%mod)
    else:
        print(0)


Verdicts: Runtime Error

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
import sys

cin = sys.stdin
cin = open("in.txt", "r")

MODULO = int(10**9+7)
N = int(cin.readline())
A = list(map(int, cin.readline().split()))
pos = [0]*(N)
if (N%2==1):
    pos[N//2+1]=1
for ai in A:
    if (ai+N)%2==0:
        print(0)
        exit()
    pos[ai]+=1
    if pos[ai]>2:
        print(0)
        exit()
cnt = 1
for i in range(N//2):
    cnt = cnt * 2 % MODULO
print(cnt)

import sys

cin = sys.stdin
#cin = open("in.txt", "r")

MODULO = int(10**9+7)
N = int(cin.readline())
A = list(map(int, cin.readline().split()))
pos = [0]*(N+1)
if (N%2==1):
    pos[0]=1
for ai in A:
    if (ai+N)%2==0 or ai>=N or ai<0:
        print(0)
        exit()
    pos[ai]+=1
    if pos[ai]>2:
        print(0)
        exit()
cnt = 1
for i in range(N//2):
    cnt = cnt * 2 % MODULO
print(cnt)

Verdicts: Runtime Error

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
N = int(input())
A = sorted([int(i) for i in input().split()], reverse=True)

from itertools import groupby

gr = groupby(A)

ans = 1
if N % 2 == 0:
    for _,group in gr:
        if len(tuple(group)) != 2:
            print(0)
            exit()
        else:
            ans *= 2
else:
    for key,group in gr:
        if len(tuple(group)) != 2:
            if key == 0 and len(tuple(group)) == 1:
                continue
            else:
                print(0)
                exit()
        else:
            ans *= 2

print(ans)

N = int(input())
A = [int(i) for i in input().split()]

MOD = 10**9+7

from collections import Counter
 
for key,count in sorted(Counter(A).items(), key=lambda x:x[0]):
    if key == 0 and N % 2 == 1:
        continue
    if count == 2 and key % 2 != N % 2:
        continue
    print(0)
    exit()
 

if N % 2 == 1:
    N -= 1
 
print(2 ** (N//2) % MOD)

Verdicts: Wrong Answer

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
import math
n = int(input())
lis = list(map(str,input().split()))
li = [0 for _ in range(math.ceil(n / 2))]

for i in range(n):
  li[math.floor(lis[i] / 2)] += 1
for i in range(len(li)):
  if n % 2 == 1 and i == 0:
    if li[i] != 1:
      print("0")
      exit()
  else:
    if li[i] != 2:
      print("0")
      exit()
print(2 ** (math.floor(n/2)))

n = int(input())
lis = list(map(int,input().split()))
lis.sort()
if n % 2 == 1:
    if lis[0] != 0:
        print("0")
        exit()
    else:key = 0
else:key = -1
for i in range(n//2):
    if lis[i*2+key+1] != lis[i*2+key+2] or lis[i*2+key+2] != 2*(i+1) + key:
        print("0")
        exit()
ans = 1
for i in range(n//2):
    ans *= 2
    ans %= 10 ** 9 +7
print(ans)

Verdicts: Runtime Error

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
N = int(input())
A = [int(i) for i in input().split()]

check = True
A = sorted(A)
print(A)
if N % 2 == 0:
    for i in range(N):
        if i % 2 == 0 and A[i] != i + 1:
            check = False
        if i % 2 == 1 and A[i] != i:
            check = False

if N % 2 != 0:
    for i in range(N):
        if i % 2 == 0 and A[i] != i:
            check = False
        if i % 2 == 1 and A[i] != i + 1:
            check = False

if check:
    print((2 ** (N // 2)) % (10 ** 9 + 7))
else:
    print(0)


N = int(input())
A = [int(i) for i in input().split()]

check = True
A = sorted(A)
if N % 2 == 0:
    for i in range(N):
        if i % 2 == 0 and A[i] != i + 1:
            check = False
        if i % 2 == 1 and A[i] != i:
            check = False

if N % 2 != 0:
    for i in range(N):
        if i % 2 == 0 and A[i] != i:
            check = False
        if i % 2 == 1 and A[i] != i + 1:
            check = False

if check:
    print((2 ** (N // 2)) % (10 ** 9 + 7))
else:
    print(0)


Verdicts: Wrong Answer

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
import sys
N = int(input())
A = list(map(int, input().split()))
if N%2 == 1:
  if A.count(0) != 1:
    print(0)
    sys.exit()
  i = 1
  while i <= N//2:
    if A.count(2*i) != 2:
      print(0)
      sys.exit()
    i += 1
  j = 0
  ans = 1
  while j <= N//2:
    ans = ans*2
    j += 1
  print(ans)
if N%2 == 0:
  i = 1
  while i <= N//2:
    if A.count(2*i-1) != 2:
      print(0)
      sys.exit()
    i += 1
  j = 0
  ans = 1
  while j < N//2:
    ans = ans*2
    j += 1
  print(ans)

import sys
def coun(n):
  i = 0
  ans = 1
  while i < n:
    ans = (ans*2)%(10**9+7)
    i += 1
  return ans
N = int(input())
A = list(map(int, input().split()))
A.sort()
if len(A)%2 == 1:
  if A[0]!=0:
    print(0)
    sys.exit()
  i = 1
  while i <= len(A)//2:
    if A[2*i-1]==2*i and A[2*i]==2*i:
      i += 1
    else:
      print(0)
      sys.exit()
  print(coun(N//2))

if len(A)%2 == 0:
  i = 0
  while i < N//2:
    if A[2*i] == 2*i+1 and A[2*i+1] == 2*i+1:
      i += 1
    else:
      print(0)
      sys.exit()
  print(coun(N//2))

Verdicts: Wrong Answer

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
N = int(input())
A = list(map(int, input().split()))
A = sorted(A)
f = True
if N%2 == 1:
  for i in range(N):
    if A[i] != ((i+1)//2)*2:
      f = False
      break
else:
  for i in range(N):
    if A[i] != (i//2)*2 + 1:
      f = False
      break
m = N//2
if f:
  print((2**m)//1000000007)
else:
  print(0)

N = int(input())
A = list(map(int, input().split()))
A = sorted(A)
f = True
if N%2 == 1:
  for i in range(N):
    if A[i] != ((i+1)//2)*2:
      f = False
      break
else:
  for i in range(N):
    if A[i] != (i//2)*2 + 1:
      f = False
      break
m = N//2
if f:
  print((2**m)%1000000007)
else:
  print(0)

Verdicts: Wrong Answer

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
N=int(input())
A=list(map(int,input().split()))
A.sort()

f=True
if N%2!=0:
	idx=1
	x=2
	if A[0]!=0:f=False
else:
	idx=0
	x=1
print(A)
for i in range(N//2):
	print(idx)
	if A[idx]!=x or A[idx+1]!=x:
		f=False
	idx+=2
	x+=2

if f:print(2**(N//2)%(10**9+7))
else:print(0)

N=int(input())
A=list(map(int,input().split()))
A.sort()

f=True
if N%2!=0:
	idx=1
	x=2
	if A[0]!=0:f=False
else:
	idx=0
	x=1

for i in range(N//2):
	if A[idx]!=x or A[idx+1]!=x:
		f=False
	idx+=2
	x+=2

if f:print(2**(N//2)%(10**9+7))
else:print(0)

Verdicts: Wrong Answer

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
import sys
from collections import Counter
n, *lst = map(int, sys.stdin.read().split())
lst = sorted(Counter(lst).items())
l = len(lst)
mod = 10 ** 9 + 7
if n % 2:
  for i in range(l):
    if not i:
      if lst[i][0] or lst[i][1] != 1:
        print(0)
        quit()
    if lst[i][0] != i * 2 or lst[i][1] != 2:
      print(0)
      quit()
else:
  for i in range(l):
    if lst[i][0] != i * 2 + 1 or lst[i][1] != 2:
      print(0)
      quit()
print((1 << (n >> 1)) % mod)


import sys
from collections import Counter


def main():
  n, *lst = map(int, sys.stdin.read().split())
  lst = sorted(Counter(lst).items())
  l = len(lst)
  mod = 10 ** 9 + 7
  if n % 2:
    for i in range(l):
      if not i:
        if lst[i][0] or lst[i][1] != 1:
          print(0)
          quit()
      elif lst[i][0] != i * 2 or lst[i][1] != 2:
        print(0)
        quit()
  else:
    for i in range(l):
      if lst[i][0] != i * 2 + 1 or lst[i][1] != 2:
        print(0)
        quit()
  print((1 << (n >> 1)) % mod)


if __name__ == '__main__':
  main()

Verdicts: Wrong Answer

Accepted
Problem: There are N people, conveniently numbered 1 through N. They were standing in a row yesterday, but now they are unsure of the order in which they were standing. However, each person remembered the following fact: the absolute difference of the number of the people who were standing to the left of that person, and the number of the people who were standing to the right of that person. According to their reports, the difference above for person i is A_i.  Based on these reports, find the number of the possible orders in which they were standing. Since it can be extremely large, print the answer modulo 10^9+7. Note that the reports may be incorrect and thus there may be no consistent order. In such a case, print 0.

Submission attempts (in order):
a = int(input())
x = list(map(int, input().split()))
x.sort()
x = x[::-1]
if a == 1:
  if x[0] == 0:print(1)
  else:print(0)
else:
  if a %2 == 0:
    for i in range(1,a,2):
      if not i == x[-1] and i ==x[-2]:
        x.pop()
        x.pop()
        print(0)
        break
    else:print(2**(a//2))
  else:
    for i in range(0,a,2):
      if x.pop() != 0:
        print(0)
        exit()
      if not i == x[-1] and i ==x[-2]:
        x.pop()
        x.pop()
        print(0)
        break
    else:print(2**(a//2))



a = int(input())
x = list(map(int, input().split()))
x.sort()
t =[2]
x = x[::-1]
if a == 1:
  if x[0] == 0:print(1)
  else:print(0)
else:
  if a %2 == 0:
    for i in range(1,a,2):
      if not i == x[-1] and i ==x[-2]:
        print(0)
        break
      x.pop()
      x.pop()
    else:print(2**(a//2))
  else:
    if x.pop() != 0:
      print(0)
      exit()
    for i in range(0,a,2):
      if not i == x[-1] and i ==x[-2]:
        print(0)
        break
      x.pop()
      x.pop()
    else:print(2**(a//2))


a = int(input())
x = list(map(int, input().split()))
x.sort()
t =[2]
x = x[::-1]
if a == 1:
  if x[0] == 0:print(1)
  else:print(0)
else:
  if a %2 == 0:
    for i in range(1,a,2):
      if not i == x[-1] and not i ==x[-2]:
        print(0)
        break
      x.pop()
      x.pop()
    else:print(2**(a//2))
  else:
    tttt = x.pop()
    if tttt != 0:
      print(0)
      exit()
    for i in range(0,a-2,2):
      if not i == x[-1] and not i ==x[-2]:
        print(0)
        break
      x.pop()
      x.pop()
    else:print(2**(a//2))



a = int(input())
x = list(map(int, input().split()))
x.sort()
t =[2]
x = x[::-1]
if a == 1:
  if x[0] == 0:print(1)
  else:print(0)
else:
  if a %2 == 0:
    for i in range(1,a,2):
      if i == x[-1] and i ==x[-2]:
        x.pop()
        x.pop()
      else:
        print(0)
        break
    else:print(2**(a//2))
  else:
    tttt = x.pop()
    if tttt != 0:
      print(0)
      exit()
    for i in range(0,a-2,2):
      if i == x[-1] and i ==x[-2]:
        x.pop()
        x.pop()
      else:
        print(0)
        break

    else:print(2**(a//2))

N = int(input())
A = [int(a) for a in input().split()]

A.sort()
B = [abs(a-b) for a,b in zip(range(N-1,-1,-1),range(N))]
B.sort()

if A==B:
    print(pow(2,N//2,10**9+7))
else:
    print(0)


Verdicts: Wrong Answer

Runtime Error

Wrong Answer

Wrong Answer

Accepted