题解 | #数组中只出现一次的数（其它数出现k次）#

class Solution:
    def int_overflow(self,val):
        maxint = 2147483647
        if not -maxint-1 <= val <= maxint:
            val = (val + (maxint + 1)) % (2 * (maxint + 1)) - maxint - 1
        return val

    def foundOnceNumber(self , arr , k ):
        # write code here
        res = 0
        for i in range(32):
            tmp = 0
            for num in arr:
#                if num<0:num = ((~num)+1)&0xffffffff
                tmp += num >> i & 1
            if tmp%k != 0:
                res += 1<<i
        return res-2**32 if res>>31&1 else res