private static Day16Input ConvertInput(string input)
{
var result = new Day16Input();
var groups = input.SplitOnBlankLines();
groups.Should().HaveCount(3);
result.Classes.AddRange(groups[0]
.SplitIntoLines()
.Select(line => RegexUtils.Deserialize <Day16Class>(line,
@"(?<Name>[^:]+): (?<Range1Min>\d+)-(?<Range1Max>\d+) or (?<Range2Min>\d+)-(?<Range2Max>\d+)")));
result.MyTicket =
groups[1]
.SplitIntoLines()
.Skip(1)
.Select(it => it.Split(",").Select(item => Convert.ToInt32(item)).ToList())
.Single();
result.Tickets.AddRange(groups[2]
.SplitIntoLines()
.Skip(1)
.Select(it => it.Split(",").Select(item => Convert.ToInt32(item)).ToList()));
return(result);
}
private static long Part2(Day16Input input)
{
var positionToClass = GetPositions(input).ToList();
long sum = 1;
foreach (var rule in input.Classes.Where(it => it.Name.StartsWith("departure")))
{
var positionIndex = positionToClass.Select((it, index) => (it, index)).Single(it => it.it == rule).index;
sum *= input.MyTicket[positionIndex];
}
return(sum);
}
private static IEnumerable <Day16Class> GetPositions(Day16Input input)
{
var tickets = input.Tickets
.Where(ticket => ticket.All(value => input.Classes.Any(klass => klass.Validate(value))))
.ToList();
var rotated = tickets
.SelectMany(ticket => ticket.Select((it, index) => (it, index)))
.GroupBy(it => it.index)
.Select(it => it.Select(z => z.it));
var positionToClass = rotated
.Select(values => input.Classes.Where(klass => values.All(value => klass.Validate(value))).ToHashSet())
.ToArray();
var(resolved, _) = Produce.Forever((
resolved: new Day16Class[input.Tickets[0].Count],
unresolved: positionToClass.Select((it, index) => (it, index))),
state =>
{
var groups = state.unresolved
.GroupBy(ptc => ptc.it.Count == 1).ToDictionary(g => g.Key, g => g.ToList());
var unresolved = groups.TryGetValue(false, out var value)
? value
: new List <(HashSet <Day16Class> it, int index)>();
foreach (var ruleset in groups[true])
{
var rule = ruleset.it.First();
state.resolved[ruleset.index] = rule;
foreach (var otherruleset in unresolved)
{
otherruleset.it.Remove(rule);
}
}
return(state.resolved, unresolved);
})
.First(state => !state.unresolved.Any());
resolved.Should().NotContainNulls();
return(resolved);
}
public void SetUp()
{
_solver = new Day16Solver();
_input = new Day16Input();
}
private static long Part1(Day16Input input)
{
return(input.Tickets
.SelectMany(ticket => ticket.Where(value => input.Classes.All(klass => !klass.Validate(value))))
.Sum());
}
