public string PartB()
{
string filePath = @"Sixteen\DaySixteenInput_Rules.txt";
TicketEvaluator evaluator = new TicketEvaluator(filePath);
filePath = @"Sixteen\DaySixteenInput_Tickets.txt";
List <Ticket> tickets = FileUtility.ParseFileToList(filePath, line => new Ticket(line));
Dictionary <int, int> fieldOrder = DeterminedMatchedFieldOrder(tickets, evaluator);
List <int> myTicket = new List <int>()
{
53, 101, 83, 151, 127, 131, 103, 61, 73, 71, 97, 89, 113, 67, 149, 163, 139, 59, 79, 137
};
List <int> interestedFields = new List <int>()
{
0, 1, 2, 3, 4, 5
};
// I got int.Max when I first did this, so entry is clearly a long
long result = 1;
for (int i = 0; i < interestedFields.Count; i++)
{
int index = fieldOrder[interestedFields[i]];
result *= myTicket[index];
}
return(result.ToString());
}
public string PartA()
{
string filePath = @"Sixteen\DaySixteenInput_Rules.txt";
TicketEvaluator evaluator = new TicketEvaluator(filePath);
filePath = @"Sixteen\DaySixteenInput_Tickets.txt";
List <Ticket> tickets = FileUtility.ParseFileToList(filePath, line => new Ticket(line));
int errorRate = FindTicketErrorRate(tickets, evaluator);
return(errorRate.ToString());
}
public Dictionary <int, int> DeterminedMatchedFieldOrder(List <Ticket> tickets, TicketEvaluator evaluator)
{
List <Ticket> validTickets = tickets.Where(t => evaluator.IsValid(t)).ToList();
Dictionary <int, HashSet <int> > validRuleFields = evaluator.GetValidFieldPositionsForTickets(validTickets);
Dictionary <int, int> finalFieldLocation = new Dictionary <int, int>();
// As a performance improvement, work with the fields with the fewest options first
// My original brute force method using a queue and all possibilities ran to system out of memorty
var ordered = validRuleFields.OrderBy(x => x.Value.Count).ToDictionary(x => x.Key, x => x.Value);
// Rule locations already removed
List <int> toRemove = new List <int>();
foreach (var t in ordered)
{
if (t.Value.Count == 1)
{
toRemove.AddRange(t.Value);
finalFieldLocation.Add(t.Key, t.Value.First());
continue;
}
List <int> s = t.Value.Except(toRemove).ToList();
toRemove.Add(s.First());
finalFieldLocation.Add(t.Key, s.First());
}
return(finalFieldLocation);
}
public int FindTicketErrorRate(List <Ticket> tickets, TicketEvaluator evaluator)
{
return(tickets.Sum(t => evaluator.SumInvalidFields(t)));
}