// Count how many strings match rule 0.
public string PartOne(string[] lines)
{
var chunks = lines.ChunkBy(string.IsNullOrEmpty, true).Select(Enumerable.ToArray).ToArray();
var compiler = new RuleToRegexCompiler(chunks[0]);
return(chunks[1].Count(line => Regex.IsMatch(line, compiler.RuleZeroRegex)).ToString());
}
// Count how many strings match rule 0 if rules 8 and 11 were modified to loop with themselves.
public string PartTwo(string[] lines)
{
var chunks = lines.ChunkBy(string.IsNullOrEmpty, true).Select(Enumerable.ToArray).ToArray();
var compiler = new RuleToRegexCompiler(chunks[0],
loopRules: new Dictionary <int, string> {
{ 8, "42 8" }, { 11, "42 11 31" }
},
longestInputSize: chunks[1].Max(s => s.Length));
return(chunks[1].Count(line => Regex.IsMatch(line, compiler.RuleZeroRegex)).ToString());
}
