Problem

# Time:  O(logn) = O(1)
# Space: O(1)
# 
# Divide two integers without using multiplication, division and mod operator.

AC

class Solution():
    def divide(self, dividend, divisor):
        positive = (dividend < 0) is (divisor < 0)
        dividend, divisor = abs(dividend), abs(divisor)
        res = 0
        while dividend >= divisor:
            temp, i = divisor, 1
            while dividend >= temp:
                dividend -= temp
                res += i
                i <<= 1
                temp <<= 1
        if not positive:
            res = -res
        return min(max(-2**31, res), 2**31-1)


if __name__ == "__main__":
    assert Solution().divide(123, 12) == 10
    assert Solution().divide(123, -12) == -10
    assert Solution().divide(-123, 12) == -10
    assert Solution().divide(-123, -12) == 10