29. 两数相除 @Python @Go

原题

https://leetcode.cn/problems/divide-two-integers/description/

思路

倍增除数

复杂度

时间：O(log(n))
空间：O(1)

Python代码

class Solution:
    def divide(self, dividend: int, divisor: int) -> int:
        # 符号
        sign = 1 if (dividend > 0 and divisor > 0 ) or (dividend < 0 and divisor < 0) else -1 
        ans = 0 
        # 求绝对值
        dividend, divisor = abs(dividend), abs(divisor)
        while dividend >= divisor:
            # 临时除数
            temp = divisor
            # 商
            quotient = 1 
            while dividend >= temp + temp:
                temp += temp
                quotient += quotient
            ans += quotient
            dividend -= temp
        # 乘以符号
        ans *= sign
        # 确定范围
        return max(-2**31, min(ans, 2**31 - 1))
      

Go代码

func divide(dividend int, divisor int) int {
	// 符号
	var sign int
	if (dividend > 0 && divisor > 0) || (dividend < 0 && divisor < 0) {
		sign = 1
	} else {
		sign = -1
	}
	ans := 0
	// 求绝对值
	if dividend < 0 {
		dividend = -dividend
	}
	if divisor < 0 {
		divisor = -divisor
	}
	for dividend >= divisor {
		// 临时除数
		temp := divisor
		// 商
		quotient := 1
		for dividend >= temp+temp {
			temp += temp
			quotient += quotient
		}
		ans += quotient
		dividend -= temp
	}
	// 乘以符号
	ans *= sign
	// 确定范围
	return max(math.MinInt32, min(ans, math.MaxInt32))
}