Submission #1000888

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Source Code Expand

n = input()
A = [int(raw_input()) for i in xrange(n)]
rest = 0
bits = [0]*32
rbits = [0]*32
for i in xrange(n):
    comm = A[i] & (A[i] - 1)
    rest ^= comm
    bit = (A[i] - comm).bit_length()
    bits[bit] += 1
for i in xrange(32):
    if (rest >> i) & 1:
        rbits[i+1] = 1
ans = 0
for i in xrange(31):
    if rbits[31-i] and not bits[31-i]:
        print -1
        exit(0)
    if bits[31-i] and not rbits[31-i]:
        ans += 1
        for j in xrange(i, 31):
            rbits[31-j] ^= 1
su = 0
for i in xrange(31):
    su += (bool(bits[31-i])^rbits[31-i])
print -1 if su else ans

Submission Info

Judge Result