Submission #1070531

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Source Code Expand

from collections import Counter
n = input()
a = [int(x) for x in raw_input().split()]
a.sort()
c = 0
if n&1:
    if a[0] == 0:
        del a[0]
        d = Counter(a)
        for i in d.keys():
            if i == 0:
                print 0
                exit(1)
            if i&1:
                print 0
                exit(1)
            if not(i&1):
                if d[i] == 2:
                    c += 1
                if d[i] != 2:
                    print 0
                    exit(1)
    if c == (n-1)//2:
        print (1 << c)%(10**9+7)
if not(n&1):
    d = Counter(a)
    for i in d.keys():
        if i&1:
            if d[i] == 2:
                c +=1
            if d[i] != 2:
                print 0
                exit(1)
        if not(i&1):
            print 0
            exit(1)
    if c == n//2:
        print (1 << c)%(10**9+7)

Submission Info

Judge Result