private bool ValidatePassport(string passport, int version)
{
var requiredFields = new HashSet <string>()
{
"byr", "iyr", "eyr", "hgt", "hcl", "ecl", "pid"
};
var fields = StringParsers.SplitDelimitedStringIntoStringList(passport, new char[0]);
foreach (var field in fields)
{
var fieldAndValue = field.Split(':');
var fieldName = fieldAndValue[0];
var value = fieldAndValue[1];
if (ValidateField(fieldName, value, version))
{
if (requiredFields.Contains(fieldName))
{
requiredFields.Remove(fieldName);
}
}
}
return(requiredFields.Count() == 0);
}
public string SolveFirstStar(StreamReader reader)
{
var estimate = int.Parse(reader.ReadLine());
var nextLine = reader.ReadLine();
var buses = StringParsers.SplitDelimitedStringIntoStringList(nextLine, ",".ToCharArray());
long shortestWait = Int64.MaxValue;
int closestBus = 0;
foreach (var bus in buses)
{
if (bus == "x")
{
continue;
}
var busInterval = int.Parse(bus);
// Effectively computes -estimate % busInterval, picks the smallest positive unique solution
var waitTime = (-estimate % busInterval + busInterval) % busInterval;
if (waitTime < shortestWait)
{
shortestWait = waitTime;
closestBus = busInterval;
}
}
return((shortestWait * closestBus).ToString());
}
public string SolveSecondStar(StreamReader reader)
{
// Ignore first line of file
reader.ReadLine();
var nextLine = reader.ReadLine();
var buses = StringParsers.SplitDelimitedStringIntoStringList(nextLine, ",".ToCharArray());
var busIntervals = new List <long>();
var busDepartures = new List <int>();
for (int i = 0; i < buses.Count(); i++)
{
var busInterval = buses[i];
if (busInterval != "x")
{
busIntervals.Add(uint.Parse(busInterval));
busDepartures.Add(i);
}
}
// We have a list of bus intervals that looks like this:
// busIntervals = [ n0, n1, n2, ... ]
// We also have a list of required departure times for each bus (relative to the departure of bus n0):
// busDepartures = [ 0, 1, 5, ... ]
// This can be interpreted as n1 leaves at time t=0, n2 leaves at time t=1, n3 leaves at time t=5...
// We can generalize this to say:
// busIntervals[i] leaves busDepartures[i] minutes after bus n0, for 0 <= i < busIntervals.Count();
// For a given n0 departure time t, we can compute the wait time from t to the departure of bus[i] as follows:
// actualDeparture[0] = 0
// actualDeparture[i] = -t mod busIntervals[i]
// We are looking for an n0 departure time t such that -t = busDepartures[i] (mod busIntervals[i])
// This problem is a system of congruence equations of the form x = a[i] (mod n[i]) for 0 <= i <= busIntervals.Count()
var solution = SolveSystemOfCongruenceEquations(busIntervals, busDepartures);
// The solution we get back is the single unique solution that exists in the interval (-N, 0)
// where N is defined below. The way we defined the problem, the solution to this system is equivalent to -t,
// so to find that actual value of t we need to multiply by -1
return((-solution).ToString());
}
private void BuildBagList(List <string> listOfDefinitions)
{
BagList = new Dictionary <string, Bag>();
foreach (var definition in listOfDefinitions)
{
var bagAndInnerBags = definition.Split("bags contain").Select(x => x.Trim()).ToList();
var currentBagColor = bagAndInnerBags[0];
var innerBags = StringParsers.SplitDelimitedStringIntoStringList(bagAndInnerBags[1], ",".ToCharArray());
var currentBag = GetOrCreateBag(currentBagColor);
if (bagAndInnerBags[1] != "no other bags.")
{
foreach (var innerBagDescription in innerBags)
{
var innerBagTuple = CreateBagTuple(innerBagDescription);
currentBag.InnerBags.Add(innerBagTuple);
var innerBag = GetOrCreateBag(innerBagTuple.Item2);
innerBag.ParentColors.Add(currentBagColor);
}
}
}
}