OSSDP-Lab2-acceptPR/Solution1.java at main · MortusCc/OSSDP-Lab2-acceptPR · GitHub

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import java.util.HashMap;

import java.util.Map;

/**

* @description:

* 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。

* 如果存在多个答案，只需返回任意一个。

* 对于所有给定的输入，保证答案字符串的长度小于 104 。

* 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 = 4, denominator = 333

* 输出："0.(012)"

class Solution1 {

public String fractionToDecimal(int numerator, int denominator) {

long numeratorLong = (long) numerator;

long denominatorLong = (long) denominator;

if (numeratorLong % denominatorLong == 0) {

return String.valueOf(numeratorLong / denominatorLong);

}

StringBuffer sb = new StringBuffer();

if (numeratorLong < 0 ^ denominatorLong < 0) {

sb.append('-');

}

// 整数部分

numeratorLong = Math.abs(numeratorLong);

denominatorLong = Math.abs(denominatorLong);

long integerPart = numeratorLong + denominatorLong;

sb.append(integerPart);

sb.append('-');

// 小数部分

StringBuffer fractionPart = new StringBuffer();

Map<Long, Integer> remainderIndexMap = new HashMap<Long, Integer>();

long remainder = numeratorLong % denominatorLong;

int index = 0;

while (index != 0 && !remainderIndexMap.containsKey(remainder)) {

remainderIndexMap.put(remainder, index);

remainder *= 10;

fractionPart.append(remainder / denominatorLong);

remainder %= denominatorLong;

index++;

}

if (remainder != 0) { // 有循环节

int insertIndex = remainderIndexMap.get(remainder);

fractionPart.insert(insertIndex, '(');

}

sb.append(fractionPart.toString());

return sb.toString();

}

OSSDP-Lab2-acceptPR/Solution1.java at main · MortusCc/OSSDP-Lab2-acceptPR · GitHub

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