//a recursive function to get a node's value
private static int GetNodeValue(LicenseNode n)
{
if (n.Nodes.Length == 0)
{
return(n.Metadata.Sum());
}
else
{
int sum = 0;
foreach (int ptr in n.Metadata)
{
if (ptr > 0 && ptr <= n.Nodes.Length)
{
sum += GetNodeValue(n.Nodes[ptr - 1]);
}
}
return(sum);
}
}
static void Main(string[] args)
{
//read input into an array
String[] input = System.IO.File.ReadAllText("input.txt").Split(' ');
int[] license = new int[input.Length];
for (int i = 0; i < input.Length; i++)
{
license[i] = int.Parse(input[i]);
}
int checksum = 0;
int index = 0; //bookmark in the license
//read the first node to kick off the recursive read
LicenseNode root = ReadNode(ref index, ref license, ref checksum);
Console.WriteLine("First answer: " + checksum);
//walk the tree to get root's value
checksum = GetNodeValue(root);
Console.WriteLine("Second answer: " + checksum);
Console.Read();
}
//a recursive function to read in a node
private static LicenseNode ReadNode(ref int index, ref int[] license, ref int checksum)
{
//read number of child nodes and metadata
LicenseNode temp = new LicenseNode(license[index], license[index + 1]);
index += 2;
//read nodes (if present)
for (int i = 0; i < temp.Nodes.Length; i++)
{
temp.Nodes[i] = ReadNode(ref index, ref license, ref checksum);
}
//read metadata
for (int i = 0; i < temp.Metadata.Length; i++)
{
temp.Metadata[i] = license[index];
checksum += license[index];
index++;
}
return(temp);
}