/// <summary>
/// Inserts the given customer at the best location if possible.
/// </summary>
/// <param name="tour">The tour to insert into.</param>
/// <param name="weights">The directed weights.</param>
/// <param name="turnPenalties">The turn pentalties.</param>
/// <param name="customer">The customer to insert.</param>
/// <param name="metric">The metric to use, time, distance or custom.</param>
/// <param name="max">The maximum allowed cost of the insertion.</param>
public static Weight InsertCheapestDirected(this Tour tour, Weight[][] weights, Weight[] turnPenalties, ProfileMetric metric, int customer, Weight max)
{
if (tour.Count == 1)
{ // there is only one customer, the first one in the route.
if (tour.First == tour.Last)
{ // there is one customer but it's both the start and the end.
var firstId = DirectedHelper.ExtractId(tour.First);
var bestCost = new Weight()
{
Distance = float.MaxValue,
Time = float.MaxValue,
Value = float.MaxValue
};
var bestDirected1Id = int.MaxValue;
var bestDirected2Id = int.MaxValue;
for (var turn1 = 0; turn1 < 4; turn1++)
{
var firstDirectedId = DirectedHelper.BuildDirectedId(firstId, turn1);
var firstArrivalId = DirectedHelper.ExtractArrivalId(firstDirectedId);
var firstDepartureId = DirectedHelper.ExtractDepartureId(firstDirectedId);
for (var turn2 = 0; turn2 < 4; turn2++)
{
var customerDirectedId = DirectedHelper.BuildDirectedId(customer, turn2);
var customerArrivalId = DirectedHelper.ExtractArrivalId(customerDirectedId);
var customerDepartureId = DirectedHelper.ExtractDepartureId(customerDirectedId);
var weight = turnPenalties[turn1];
weight += turnPenalties[turn2];
weight += weights[firstDepartureId][customerArrivalId];
weight += weights[customerDepartureId][firstArrivalId];
if (bestCost.GetForMetric(metric) > weight.GetForMetric(metric))
{
bestDirected1Id = firstDirectedId;
bestDirected2Id = customerDirectedId;
bestCost = weight;
}
}
}
if (bestCost.GetForMetric(metric) <= max.GetForMetric(metric))
{
tour.Replace(tour.First, bestDirected1Id);
tour.InsertAfter(tour.First, bestDirected2Id);
return bestCost;
}
}
else
{ // there is one customer, the last one is not set.
var firstId = DirectedHelper.ExtractId(tour.First);
int departureOffset1, arrivalOffset2;
var cost = DirectedHelper.CheapestInsert(weights, turnPenalties,
firstId, customer, metric, out departureOffset1, out arrivalOffset2);
if (cost.GetForMetric(metric) <= max.GetForMetric(metric))
{
var newFirst = DirectedHelper.UpdateDepartureOffset(
DirectedHelper.BuildDirectedId(firstId, 0), departureOffset1);
var customerDirectedId = DirectedHelper.UpdateArrivalOffset(
DirectedHelper.BuildDirectedId(customer, 0), arrivalOffset2);
tour.Replace(tour.First, newFirst);
tour.InsertAfter(tour.First, customerDirectedId);
return cost;
}
}
}
else
{ // at least 2 customers already exist, insert a new one in between.
var cost = Weight.MaxValue;
var departureOffsetFrom = Constants.NOT_SET;
var arrivalOffsetTo = Constants.NOT_SET;
var turn = Constants.NOT_SET;
var location = new Pair(int.MaxValue, int.MaxValue);
foreach (var pair in tour.Pairs())
{
int departureOffset1, arrivalOffset3, turn2;
var fromIsFirst = tour.IsFirst(pair.From);
var toIsLast = tour.IsLast(pair.To);
var localCost = CheapestInsertionDirectedHelper.CalculateCheapestInsert(weights, turnPenalties, metric, pair.From, customer, pair.To,
!fromIsFirst, !toIsLast, out departureOffset1, out arrivalOffset3, out turn2);
if (localCost.GetForMetric(metric) < cost.GetForMetric(metric))
{
cost = localCost;
location = pair;
departureOffsetFrom = departureOffset1;
arrivalOffsetTo = arrivalOffset3;
turn = turn2;
}
}
if (cost.GetForMetric(metric) <= max.GetForMetric(metric))
{
var directedId = DirectedHelper.BuildDirectedId(customer, turn);
tour.InsertAfter(location.From, directedId);
// update departure offset at from.
var newFromId = DirectedHelper.UpdateDepartureOffset(location.From, departureOffsetFrom);
if (location.From != newFromId)
{
tour.Replace(location.From, newFromId);
}
var newToId = DirectedHelper.UpdateArrivalOffset(location.To, arrivalOffsetTo);
if (location.To != newToId)
{
tour.Replace(location.To, newToId);
}
return cost;
}
}
return Weight.Zero; // insert failed, probably costs are too high (above given max parameter).
}