private static (IDictionary <string, Rule>, List <string>) Parse(List <string> lines)
{
var rules = new Dictionary <string, Rule>();
var messages = new List <string>();
foreach (var line in lines)
{
if (OrRule.MatchesRuleDescription(line))
{
var rule = OrRule.Parse(line);
rules.Add(rule.Id, rule);
}
else if (MatchRule.MatchesRuleDescription(line))
{
MatchRule matchRule = MatchRule.Parse(line);
rules.Add(matchRule.Id, matchRule);
}
else if (SequenceRule.MatchesRuleDescription(line))
{
SequenceRule sequenceRule = SequenceRule.Parse(line);
rules.Add(sequenceRule.Id, sequenceRule);
}
else if (!string.IsNullOrEmpty(line))
{
messages.Add(line);
}
}
return(rules, messages);
}
public Tuple <Dictionary <int, Rule>, string[]> ParseInput()
{
var lines = Input.Split("\n", StringSplitOptions.TrimEntries);
var i = 0;
var rules = new Dictionary <int, Rule>();
while (!string.IsNullOrEmpty(lines[i]))
{
var a = lines[i].Split(':', StringSplitOptions.TrimEntries);
int r = int.Parse(a[0]);
if (a[1].Contains('\"'))
{
rules[r] = BasicRule.Parse(a[1]);
}
else if (a[1].Contains('|'))
{
rules[r] = OrRule.Parse(a[1]);
}
else
{
rules[r] = MultiRule.Parse(a[1]);
}
i++;
}
return(Tuple.Create(rules, lines.Skip(i + 1).ToArray()));
}
private static int MatchesRule0Cyclic(List <string> lines)
{
var(newRules, messages) = Parse(lines);
newRules["8"] = OrRule.Parse("8: 42 | 42 8");
newRules["11"] = OrRule.Parse("11: 42 31 | 42 11 31");
var result = messages.Count(message => newRules["0"].IsValid(message, newRules));
return(result);
}
protected override string SolvePartTwo()
{
var parse = ParseInput();
rules = parse.Item1;
rules[8] = OrRule.Parse("42 | 42 8");
rules[11] = OrRule.Parse("42 31 | 42 11 31");
var lines = parse.Item2;
return(lines.Select(x => Tuple.Create(x, rules[0].Match(x))).Where(x => x.Item2.Length > 0 && x.Item2.Any(y => y == x.Item1.Length - 1)).Count().ToString());
}