class Solution(object):
def divide(self, dividend, divisor):
"""
:type dividend: int
:type divisor: int
:rtype: int
"""
if dividend == 0: return 0
if divisor == 0: return
sign = -1 if ((dividend < 0) ^ (divisor < 0)) else 1 #标记是否为负
dividend = abs(dividend)
divisor = abs(divisor)
quotient = 0
tmp = 0
for i in range(32,-1,-1): #逆序枚举,范围为[0,32]
if tmp + (divisor << i) <= dividend:
tmp += divisor << i #更新tmp的值
quotient |= 1 << i #记录i的位置,从2进制的或运算就是有1就为1
quotient *= sign #虽然题目说了不要用乘法,但是为了代码的简洁这里还是用了
if quotient < -(2 ** 31) or quotient > 2 ** 31 - 1:
return 2 ** 31 - 1
else:
return quotient
AC