public static string ToRoman(this int number)
{
var freq = new FrequencyCounter <string>();
foreach (var mapping in _base10Mappings.OrderByDescending(m => m.Item2))
{
if (number < 1)
{
break;
}
var result = number.DivideBy(mapping.Item2);
number = result.Remainder;
freq[mapping.Item1] = result.Quotient;
}
var output = new StringBuilder();
foreach (var result in freq.GetItemFrequencies())
{
if (result.Count == 0)
{
continue;
}
if (result.Count == 4 && _groupingLookup.ContainsKey(result.Item))
{
output.Append(result.Item + _groupingLookup[result.Item]);
continue;
}
if (result.Count == 9 && _base10Mappings[_base10Mappings[result.Item] * 10] != null)
{
output.Append(result.Item + _base10Mappings[_base10Mappings[result.Item] * 10]);
continue;
}
if (result.Count > 4 && _groupingLookup.ContainsKey(result.Item)) // 5, 6, 7, 8
{
output.Append(_groupingLookup[result.Item] + result.Item.Repeat(result.Count - 5));
continue;
}
output.Append(result.Item.Repeat(result.Count));
}
return(output.ToString());
}
public static int GetRomanValue(this string roman)
{
var value = 0;
foreach (var pair in _validSubractivePairs)
{
if (!roman.Contains(pair))
{
continue;
}
value += GetSubtractivePairValue(pair);
roman = roman.Replace(pair, string.Empty);
}
var freq = new FrequencyCounter <string>();
foreach (var mapping in _allMappings)
{
freq[mapping.Item1] = roman.Count(c => c.ToString() == mapping.Item1);
}
return(value + freq.GetItemFrequencies().Sum(result => result.Count * _allMappings[result.Item]));;
}