Description

实现除法(保留整数)

Solution

被除数每次*2
ans每次加1<<shift num

class Solution(object):
    def divide(self, dividend, divisor):
        INT_MAX = 2147483647
        if divisor == 0:
            return INT_MAX
        neg = dividend > 0 and divisor < 0 or dividend < 0 and divisor > 0
        a, b = abs(dividend), abs(divisor)
        ans, shift = 0, 31
        while shift >= 0:
            if a >= b << shift:
                a -= b << shift
                ans += 1 << shift
            shift -= 1
        if neg:
            ans = - ans
        if ans > INT_MAX:
            return INT_MAX
        return ans