private Result SolveRecursively(NodeState currentState)
{
// check if done:
var collaboratingSensorGroups =
currentState.Variables.Where(v => v.IsAssigned).GroupBy(v => v.AssignedValue).ToArray();
var done = collaboratingSensorGroups.Length == DomainValues.Count &&
collaboratingSensorGroups.All(group => group.Count() == NeededSensorsForEachTargetNo);
if (done)
{
return new Result()
{
AssignedVariables = currentState.Variables.ToDictionary(v => v.Name)
}
}
;
var variableToAssign = GetNextVariable(currentState);
if (variableToAssign is null)
{
throw new CspPathFailure(currentState);
}
var stateBeforeGoingDeeper = currentState.Clone();
foreach (var value in GetValueFor(variableToAssign))
{
if (!IsConsistent(currentState, variableToAssign, value))
{
continue;
}
variableToAssign.AssignedValue = value.Value;
variableToAssign.IsAssigned = true;
// forward checking
UpdateCandidates(currentState.Variables, value);
try
{
return(SolveRecursively(currentState));
}
catch (CspPathFailure)
{
currentState.GoBackToState(stateBeforeGoingDeeper);
}
}
// try going deep leaving variableToAssign unassigned!
variableToAssign.IsAncestorWithoutValue = true;
try
{
return(SolveRecursively(currentState));
}
catch (CspPathFailure)
{
currentState.GoBackToState(stateBeforeGoingDeeper);
throw;
}
}
