【剑指offer】Q40：数组中出现一次的数

def once(array):

reOR = 0
for x in array:
reOR ^= x

bit1 = firstBit1(reOR)
first = 0
second = 0
for x in array:
if x & bit1 != 0:
first ^= x
else:
second ^= x
return first, second

def firstBit1(x):
n = 1
while True:
if x & n != 0:
return n
else:
n <<= 1