Leetcode 29. 两数相除

class Solution:
    '''
    倍增divisor，每次将结果保存到divisor_multiadd_list，
    divisor_multiadd_list[k]=2^k * divisor
    '''
    def divide(self, dividend: int, divisor: int) -> int:
        #溢出处理
        if dividend==-2**31 and divisor==-1:
            return 2**31-1
        flag=1 if dividend^divisor >=0 else -1
        dividend,divisor=abs(dividend),abs(divisor)
        divisor_multiadd_list=[]
        while divisor<=dividend:
            divisor_multiadd_list.append(divisor)
            divisor+=divisor
        ans=0
        for idx in range(len(divisor_multiadd_list)-1,-1,-1):
            if dividend>=divisor_multiadd_list[idx]:
                dividend-=divisor_multiadd_list[idx]
                ans+=2**idx
        return flag*ans