[Leetcode 166, Medium] Fraction to Recurring Decimal

来源：互联网发布：算法实现约瑟夫环c语言编辑：程序博客网时间：2024/05/19 16:03

Problem:

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)".

Analysis:

Solutions:

C++:

    string NumericToString(unsigned int num)    {        string s_num;        if(num == 0)            return "0";                    while(num) {            s_num.insert(s_num.begin(), num % 10 + '0');            num /= 10;        }                return s_num;    }        string fractionToDecimal(int numerator, int denominator) {        string decimal;        if(numerator == 0)            return "0";        if((numerator < 0 && denominator > 0) || (numerator > 0 && denominator < 0))            decimal = "-";        unsigned long long num = (numerator < 0 ? -1 : 1) * static_cast<long long>(numerator);        unsigned long long den = (denominator < 0 ? -1 : 1) * static_cast<long long>(denominator);        unsigned long long quo = num / den;        unsigned long long res = num % den;        if(num == 0)            return "0";        decimal.append(NumericToString(quo));        if(res == 0)            return decimal;        decimal.push_back('.');        num = res * 10;        map<pair<unsigned long long, unsigned long long>, int> ress;        string fraction;        while(1) {            quo = num / den;            res = num % den;            num = res * 10;            if(res != 0 && ress.find(make_pair(quo, res)) == ress.end()) {                fraction.push_back(quo + '0');                ress[make_pair(quo, res)] = fraction.size() - 1;                num = res * 10;            } else {                if(res == 0)                    fraction.push_back(quo + '0');                break;            }        }        if(res == 0)            decimal.append(fraction);        else {            cout << fraction << endl;            for(int i = 0; i < fraction.size(); ++i) {                if(i == ress[make_pair(quo, res)]) {                    decimal.push_back('(');                }                decimal.push_back(fraction[i]);            }            decimal.push_back(')');        }        return decimal;    }

Java:

Python:

0 0