static void Main(string[] args)
{
using (StreamReader input = File.OpenText("d:\\programming\\Advent of Code\\data 2019\\D14\\input.txt"))
{
string line = "";
while ((line = input.ReadLine()) != null)
{
line = line.Replace(" => ", ";").Replace(", ", ",");
// output
string[] t1 = line.Split(';');
string[] t2 = t1[1].Split(' ');
int index1 = chemicals.FindIndex(a => a.name == t2[1]);
if (index1 == -1)
{
chemicals.Add(new Chemical()
{
name = t2[1], amountProduced = Convert.ToInt64(t2[0])
});
index1 = chemicals.Count - 1;
}
else
{
chemicals[index1].amountProduced = Convert.ToInt32(t2[0]);
}
// inputs
chemicals[index1].inputs = new List <Subproduct>();
t2 = t1[0].Split(',');
for (int i = 0; i < t2.Length; i++)
{
t1 = t2[i].Split(' ');
int index2 = chemicals.FindIndex(a => a.name == t1[1]);
if (index2 == -1)
{
chemicals.Add(new Chemical()
{
name = t1[1]
});
index2 = chemicals.Count - 1;
}
chemicals[index1].inputs.Add(new Subproduct()
{
subproduct = chemicals[index2], amount = Convert.ToInt64(t1[0])
});
}
}
}
Chemical fuel = chemicals.Find(a => a.name == "FUEL");
ComputeOreAmount(ref fuel, 8193614);
Console.WriteLine(1000000000000 - chemicals.Find(a => a.name == "ORE").leftover);
Console.WriteLine("end");
Console.ReadLine();
}
static void ComputeOreAmount(ref Chemical output, Int64 amountNeeded)
{
if (output.name == "ORE")
{
output.leftover += amountNeeded;
return;
}
Int64 amount = amountNeeded - output.leftover;
if (amount == 0)
{
output.leftover = 0;
return;
}
if (amount < 0)
{
output.leftover -= amountNeeded;
return;
}
if (amount > 0)
{
output.leftover = 0;
}
Int64 mod = amount % output.amountProduced;
if (mod > 0)
{
output.leftover = output.amountProduced - mod;
}
for (int i = 0; i < output.inputs.Count; i++)
{
ComputeOreAmount(ref output.inputs[i].subproduct, output.inputs[i].amount * (amount / output.amountProduced + (mod > 0 ? 1 : 0)));
}
}