private static List <FuelInstruction> ParseInstructionsIntoRequirements(string[] instructions)
{
List <FuelInstruction> fuelInstructions = new List <FuelInstruction>();
foreach (var instruction in instructions)
{
var splitter = instruction.IndexOf("=>");
var requirements = instruction.Substring(0, splitter);
var requirementsSplit = requirements.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries).Select(x => x.Trim());
FuelInstruction fuelRequirement = new FuelInstruction();
foreach (var requirement in requirementsSplit)
{
var fuel = new Fuel();
fuel.Quantity = int.Parse(requirement.Substring(0, requirement.IndexOf(' ')));
fuel.FuelType = requirement.Substring(requirement.IndexOf(' ') + 1).Trim();
fuelRequirement.Requires.Add(fuel);
}
var produces = instruction.Substring(splitter + 2).Trim();
var producesFuel = new Fuel();
producesFuel.Quantity = int.Parse(produces.Substring(0, produces.IndexOf(' ')));
producesFuel.FuelType = produces.Substring(produces.IndexOf(' ') + 1).Trim();
fuelRequirement.Creates = producesFuel;
fuelInstructions.Add(fuelRequirement);
}
return(fuelInstructions);
}
public static void Execute()
{
var inputs = File.ReadAllLines(@"C:\Work\Misc Projects\AdventOfCode\AdventOfCode\AdventOfCode\2019\Data\day14_full.txt");
var recipes = ParseInstructionsIntoRequirements(inputs);
FuelInstruction fuel = recipes.First(x => x.Creates.FuelType == "FUEL");
Dictionary <string, int> requirements = new Dictionary <string, int>();
Dictionary <string, int> dict = CalculateOreRequired(recipes.Where(x => x.Creates.FuelType != "FUEL"), fuel, requirements, null);
int total = CalculateOreRequiredFromRequirements(dict, recipes.Where(x => x.Requires.Any(y => y.FuelType == "ORE")));
Console.WriteLine(total);
}
private static int CalculateOreRequiredFromRequirements(Dictionary <string, int> dict, IEnumerable <FuelInstruction> recipes)
{
int total = 0;
foreach (var entry in dict)
{
FuelInstruction recipe = recipes.First(x => x.Creates.FuelType == entry.Key);
int value = dict[entry.Key];
while (value > 0)
{
total += recipe.Requires[0].Quantity;
value -= recipe.Creates.Quantity;
}
}
return(total);
}
private static Dictionary <string, int> CalculateOreRequired(IEnumerable <FuelInstruction> recipes, FuelInstruction recipe, Dictionary <string, int> requirements, Fuel previousRequirement, int mult = 1)
{
foreach (var requirement in recipe.Requires)
{
if (requirement.FuelType == "ORE")
{
requirements.AddIfPossible(previousRequirement.FuelType, mult);
}
else
{
CalculateOreRequired(recipes, recipes.First(x => x.Creates.FuelType == requirement.FuelType), requirements, requirement, mult * requirement.Quantity);
}
}
return(requirements);
}