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| // @Title: 分数到小数 (Fraction to Recurring Decimal)
// @Author: 15816537946@163.com
// @Date: 2019-09-03 18:26:11
// @Runtime: 0 ms
// @Memory: 2.8 MB
/*
* @lc app=leetcode.cn id=166 lang=golang
*
* [166] 分数到小数
*
* https://leetcode-cn.com/problems/fraction-to-recurring-decimal/description/
*
* algorithms
* Medium (24.58%)
* Likes: 60
* Dislikes: 0
* Total Accepted: 4.5K
* Total Submissions: 18.4K
* Testcase Example: '1\n2'
*
* 给定两个整数,分别表示分数的分子 numerator 和分母 denominator,以字符串形式返回小数。
*
* 如果小数部分为循环小数,则将循环的部分括在括号内。
*
* 示例 1:
*
* 输入: numerator = 1, denominator = 2
* 输出: "0.5"
*
*
* 示例 2:
*
* 输入: numerator = 2, denominator = 1
* 输出: "2"
*
* 示例 3:
*
* 输入: numerator = 2, denominator = 3
* 输出: "0.(6)"
*
*
*/
func fractionToDecimal(numerator int, denominator int) string {
// 处理0
if numerator == 0 {
return "0"
}
// 符号处理
sign := 1
if numerator < 0 {
numerator = -numerator
sign = -sign
}
if denominator < 0 {
denominator = -denominator
sign = - sign
}
// 整数处理
intpart := 0
if numerator > denominator {
intpart = numerator/denominator
}
numerator %= denominator
// 小数部分
floatpart := make([]int,0)
remainmap := make(map[int]int)
idx := -1
for numerator > 0 {
if _, ok := remainmap[numerator];ok {
idx = remainmap[numerator]
break
}
// 记录当前余数
remainmap[numerator] = len(floatpart)
// 除法计算过程
numerator = numerator * 10
f := numerator / denominator
floatpart = append(floatpart, f)
numerator = numerator % denominator
}
// 计算结果
s := ""
if sign < 0 {
s += "-"
}
s += fmt.Sprintf("%d", intpart)
if len(floatpart) > 0 {
s += "."
for i := range floatpart {
if idx >= 0 && i == idx {
s+= "("
}
s += fmt.Sprintf("%d", floatpart[i])
}
if idx >= 0 {
s += ")"
}
}
return s
}
|