public void ExecuteDanceSteps()
{
DanceStepParser p = new DanceStepParser();
var steps = p.ParseSteps("s1,x3/4,pe/b");
DanceExecutor e = new DanceExecutor(new char[] { 'a', 'b', 'c', 'd', 'e' });
Assert.Equal(new char[] { 'b', 'a', 'e', 'd', 'c' }, e.Execute(steps));
}
static void Main(string[] args)
{
var rawInput = System.IO.File.ReadAllText("Inputs/day-16.txt").Trim();
var startingPrograms = new char[] { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h',
'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p' };
DanceStepParser p = new DanceStepParser();
var steps = p.ParseSteps(rawInput);
DanceExecutor e = new DanceExecutor(startingPrograms);
var dance = e.Execute(steps);
// Set up a dictionary to memoize the results of each call to
// the dance executor.
Dictionary <string, char[]> cache = new Dictionary <string, char[]>();
cache.Add(String.Join("", startingPrograms), dance);
// Part one
Console.WriteLine(String.Join("", dance));
// Part two
for (long i = 1; i < 1_000_000_000; i++)
{
var key = String.Join("", dance);
if (cache.ContainsKey(key))
{
dance = cache[key];
}
else
{
e = new DanceExecutor(dance);
dance = e.Execute(steps);
cache.Add(key, dance);
}
}
Console.WriteLine(String.Join("", dance));
}