leetcode oj 166. Fraction to Recurring Decimal 除法

FengTwoYear

于 2016-12-25 16:23:58 发布

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CC 4.0 BY-SA版权

本文链接：https://blog.youkuaiyun.com/FengTwoYear/article/details/53870475

本文介绍了一个C++程序，该程序可以将任意两个整数表示的分数转换为字符串格式的小数。如果小数部分存在循环节，则会在循环部分使用括号进行标记。例如，输入分子2和分母3时，输出结果为“0.(6)”。文章提供了完整的代码实现。

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Given two integers representing the numerator and denominator of a fraction, return the fraction in string format.

If the fractional part is repeating, enclose the repeating part in parentheses.

For example,

Given numerator = 1, denominator = 2, return "0.5".
Given numerator = 2, denominator = 1, return "2".

Given numerator = 2, denominator = 3, return "0.(6)".

class Solution
{
public:
    string fractionToDecimal(int numerator, int denominator)
    {
        if(numerator==0)
            return "0";
        long num1=fabs(numerator);
        long num2=fabs(denominator);
        int flag=(numerator>0^denominator>0)?1:0;
        string ans=flag?"-":"";
        ans+=to_string(num1/num2);
        if(num1%num2==0)
            return ans;
        unordered_map<int ,int>hash;
        num1=num1%num2;
        ans+=".";
        while(!hash.count(num1))
        {
            hash[num1]=ans.size();
            num1*=10;
            ans+=to_string(num1/num2);
            if(num1%num2==0)
                return ans;
            num1=num1%num2;
        }
      int len=ans.size();
     
       ans.insert(hash[num1], 1, '(');
        ans += ')';
        return ans;
    }
};