public Dictionary <int, string> GetValidFieldPositions()
{
//< Get all nearby, valid tix
var validTix = Nearby.Where(x => x.IsValid(this));
//< Instantiate a hashset of all 'solved' notes and a map of which indices have been solved by what note
var usedFields = new HashSet <string>();
var positions = new Dictionary <int, string>();
//< Grab the ticket count so we know how values a note must cover to be a potential solution
int ticketCount = validTix.Count();
//< Need to solve for each position within the tickets
while (usedFields.Count != Mine.Length)
{
foreach (int i in Enumerable.Range(0, Mine.Length))
{
if (positions.ContainsKey(i))
{
//< Already solved - skip
continue;
}
//< Get all the values at this position in the ticket from nearby, valid tix
var vals = validTix.Select(x => x.GetValue(i));
//< Get the map of number of times a note covered a value in this index
var noteMap = GetNoteMap(vals);
//< Get the matching notes (notes which were covered by all tix)
var matching = noteMap.Where(kvp => !usedFields.Contains(kvp.Key))
.Where(kvp => kvp.Value == ticketCount);
//< Switch on the resulting count - if more than one, need to solve other positions first
if (matching.Count() > 1)
{
//< Can't decide yet - retain for later check
}
else
{
//< Only one solution here - use it and move on
var match = matching.Single();
positions.Add(i, match.Key);
usedFields.Add(match.Key);
}
}
}
return(positions);
}
public Tickets(string fields, string nearbyTickets, string myTicket)
{
Fields = fields
.SplitLines()
.Select(x => new Field(x))
.ToList();
Nearby = nearbyTickets
.SplitLines()
.Select(x => new Ticket(x.SplitOn(',').Select(int.Parse), Fields))
.ToList();
MyTicket = new Ticket(myTicket.SplitOn(',').Select(int.Parse), Fields);
ValidTickets = new List <Ticket>(Nearby.Where(x => x.IsValid))
{
MyTicket
};
}