LeetCode -- Fraction to Recurring Decimal

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public class Solution {
    public string FractionToDecimal(int numerator, int denominator) {
     if (numerator == 0)
		return "0";
	if (denominator == 0)
		return "";
 
	var result = "";
 
	// is result is negative
	if ((numerator < 0) ^ (denominator < 0)) {
		result += "-";
	}
 
	// convert int to long
	long num = numerator, den = denominator;
	num = Math.Abs(num);
	den = Math.Abs(den);
 
	// quotient 
	long res = num / den;
	result += res.ToString();
 
	// if remainder is 0, return result
	long remainder = (num % den) * 10;
	if (remainder == 0)
		return result;
 
	// right-hand side of decimal point
	Dictionary<long, int> map = new Dictionary<long, int>();
	result += ".";
	while (remainder != 0) {
		// if digits repeat
		if (map.ContainsKey(remainder)) {
			int beg = map[remainder]; 
			var part1 = result.Substring(0, beg);
			var part2 = result.Substring(beg, result.Length-beg);
			result = part1 + "(" + part2 + ")";
			return result;
		}
 
		// continue
		map.Add(remainder, result.Length);
		res = remainder / den;
		result += res.ToString();
		remainder = (remainder % den) * 10;
	}
 
	return result;
	 
    }
}

LeetCode -- Fraction to Recurring Decimal

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原文地址：http://blog.csdn.net/lan_liang/article/details/48575985