(Medium #29) Divide Two Integers

Problem

Given two integers dividend and divisor, divide two integers without using multiplication, division and mod operator.

Return the quotient after dividing dividend by divisor.

The integer division should truncate toward zero.

Example 1:

Input: dividend = 10, divisor = 3
Output: 3

Example 2:

Input: dividend = 7, divisor = -3
Output: -2

Note:

• Both dividend and divisor will be 32-bit signed integers.
• The divisor will never be 0.
• Assume we are dealing with an environment which could only store integers within the 32-bit signed integer range: [−231,  231 − 1]. For the purpose of this problem, assume that your function returns 231 − 1 when the division result overflows.

My solution

class Solution:
    def divide(self, dividend: int, divisor: int) -> int:
        MAXNUM = 2**31-1
        MINNUM = -2**31
        
        if dividend == 0:
            return 0
        if (dividend > 0 and divisor > 0) or (dividend < 0 and divisor < 0):
            sign = 1
        else:
            sign = -1
        
        dividend = abs(dividend)
        divisor = abs(divisor)
        
        if dividend < divisor:
            return 0
        
        divisor2 = divisor
        result = 0
        term = 1
        # print("1", dividend, divisor, divisor2, result)
        while True:
            if dividend < divisor2:
                break
            dividend -= divisor2
            result += term
            
            divisor2 += divisor2
            term += term
        # print("2", dividend, divisor, divisor2, result)
        result += self.divide(dividend, divisor)
                
        if sign*result > MAXNUM:
            return MAXNUM
        elif sign*result < MINNUM:
            return MINNUM
        else:
            return sign*result

Runtime: 44ms, Memory: 13.9MB