private ConversionPath GetShortestPath(ToConvert toConvert, List <ExchangeRate> exchangeRates)
{
// keys are currencies, values are for the chained calculations
// first node: <initial currency, amount>
// other nodes: <currency, exchange rate>
var firstNode = new KeyValuePair <string, float>(toConvert.InitialCurrency, toConvert.Amount);
// init with a first path with the currency to convert from
var possibilities = new List <ConversionPath> {
new ConversionPath {
Nodes = new List <KeyValuePair <string, float> > {
firstNode
}
}
};
while (exchangeRates.Any())
{
foreach (var possibility in possibilities.ToList())
{
var lastNode = possibility.Nodes.Last();
var matchingRates = exchangeRates
.Where(e => lastNode.Key == e.InitialCurrency || lastNode.Key == e.TargetCurrency)
.ToList();
if (matchingRates.Any())
{
possibilities = AddPathsFromMatches(possibilities, possibility, matchingRates);
var shortest = possibilities.FirstOrDefault(p => p.Nodes.Last().Key == toConvert.TargetCurrency);
// found the shortest path
if (shortest != null)
{
return(shortest);
}
exchangeRates.RemoveAll(e => matchingRates.Contains(e));
}
else
{
// no match, useless path
possibilities.Remove(possibility);
// remaining exchange rates but no path to solution
if (!possibilities.Any())
{
return(null);
}
break;
}
}
}
// empty list but no solution found
return(null);
}
public void Run(string filePath)
{
if (!File.Exists(filePath))
{
Console.Error.WriteLine("File path doesn't exist");
Environment.Exit(1);
}
var lines = File.ReadLines(filePath).ToList();
try
{
var instructions = ExchangeRatesTableParser.GetConversionInstructions(lines[0], lines[1]);
ToConvert toConvert = instructions.Item1;
int exchangeRatesCount = instructions.Item2;
var exchangeRates = ExchangeRatesTableParser.ParseRates(lines, exchangeRatesCount);
ConversionPath shortestPath = GetShortestPath(toConvert, exchangeRates.ToList());
if (shortestPath == null)
{
Console.Error.WriteLine("Incorrect file: no solution");
Environment.Exit(1);
}
Console.WriteLine(Math.Round(ConvertCurrency(shortestPath)));
}
catch (IndexOutOfRangeException)
{
Console.Error.WriteLine("Incorrect file: doesn't respect the exchange rates format");
Environment.Exit(1);
}
catch (FormatException)
{
Console.Error.WriteLine("Incorrect file: number of lines not provided");
Environment.Exit(1);
}
catch (IncorrectRateCountException)
{
Console.Error.WriteLine("Incorrect file: expected number of exchange rates differs from content");
return;
}
}
public static Tuple <ToConvert, int> GetConversionInstructions(string request, string exchangeRateCount)
{
string[] requestData = request.Split(';');
if (requestData.Length != 3)
{
throw new IndexOutOfRangeException();
}
else
{
ToConvert toConvert = new ToConvert {
InitialCurrency = requestData[0],
Amount = Convert.ToInt32(requestData[1]),
TargetCurrency = requestData[2]
};
int count = Convert.ToInt32(exchangeRateCount);
return(Tuple.Create(toConvert, count));
}
}
private static IEnumerable <object> GetImpls()
{
var sourceType = typeof(TSource);
var destinationType = typeof(TDestination);
// Custom
foreach (var factory in InternalConvert.factories)
{
yield return(factory.GetConverter(sourceType, destinationType));
}
// Basic
yield return(BasicConvert.Instance);
// Implicit
if (sourceType == destinationType)
{
yield return(new EqualsConvert <TSource>());
}
// Implicit
if (Nullable.GetUnderlyingType(destinationType) == sourceType)
{
yield return(Activator.CreateInstance(typeof(StructToNullableConvert <>).MakeGenericType(sourceType)));
}
// Explicit
if (Nullable.GetUnderlyingType(sourceType) == destinationType)
{
yield return(Activator.CreateInstance(typeof(NullableToStructConvert <>).MakeGenericType(destinationType)));
}
// Custom
if (destinationType == typeof(string))
{
yield return(new ToStringConvert <TSource>());
}
// Implicit
if (destinationType.IsAssignableFrom(sourceType))
{
yield return(Activator.CreateInstance(typeof(AssignableConvert <,>).MakeGenericType(sourceType, destinationType)));
}
// Custom
if (sourceType == typeof(DBNull))
{
yield return(new FromDBNullConvert <TDestination>());
}
// Custom
if (destinationType == typeof(DBNull))
{
yield return(new ToDBNullConvert <TSource>());
}
// Implicit & XConvert
{
if (Nullable.GetUnderlyingType(sourceType) is Type underlyingType && underlyingType != sourceType)
{
yield return(Activator.CreateInstance(typeof(NullableToValueConvert <,>).MakeGenericType(underlyingType, destinationType)));
}
}
// XConvert & Implicit
{
if (Nullable.GetUnderlyingType(destinationType) is Type underlyingType && underlyingType != destinationType)
{
yield return(Activator.CreateInstance(typeof(ValueToNullableConvert <,>).MakeGenericType(sourceType, underlyingType)));
}
}
// Custom
if (sourceType == typeof(string) && destinationType.IsEnum)
{
yield return(Activator.CreateInstance(typeof(ParseEnum <>).MakeGenericType(destinationType)));
}
// Implicit
if (ImplicitConvert.TryGetMathod(sourceType, destinationType, out var method))
{
yield return(BaseDynamicConvert.CreateInstanceByIL <TSource, TDestination>(method));
}
// Explicit
if (ExplicitConvert.TryGetMathod(sourceType, destinationType, out method))
{
yield return(BaseDynamicConvert.CreateInstanceByIL <TSource, TDestination>(method));
}
// Custom
if (ParseConvert.TryGetMathod(sourceType, destinationType, out method))
{
yield return(BaseDynamicConvert.CreateInstanceByIL <TSource, TDestination>(method));
}
// Custom
if (ToConvert.TryGetMathod(sourceType, destinationType, out method))
{
yield return(BaseDynamicConvert.CreateInstanceByIL <TSource, TDestination>(method));
}
// Custom
if (ConstructorConvert.TryGetMathod(sourceType, destinationType, out var constructor))
{
yield return(BaseDynamicConvert.CreateInstanceByIL <TSource, TDestination>(constructor));
}
// Explicit
if (sourceType.IsAssignableFrom(destinationType))
{
yield return(Activator.CreateInstance(typeof(BaseConvert <,>).MakeGenericType(sourceType, destinationType)));
}
// Error
yield return(new ForceConvert <TSource, TDestination>());
}