public List <State> expandState(ClosedSet closedSet)
{
List <State> returnList = new List <State>();
State tempState;
if (boatIs == LEFT)
{
// First action
tempState = new State(riverBankLeft.getCannibals() - 2, riverBankLeft.getMissionaries() - 0, riverBankRight.getCannibals() + 2, riverBankRight.getMissionaries() + 0, boatIs);
if (tempState.isValidState())
{
if (closedSet.contains_get_id(tempState) != -1)
{
tempState.id = closedSet.contains_get_id(tempState);
State.idCount--;
}
returnList.Add(tempState);
}
else
{
State.idCount--;
}
// Second action
tempState = new State(riverBankLeft.getCannibals() - 0, riverBankLeft.getMissionaries() - 2, riverBankRight.getCannibals() + 0, riverBankRight.getMissionaries() + 2, boatIs);
if (tempState.isValidState())
{
if (closedSet.contains_get_id(tempState) != -1)
{
tempState.id = closedSet.contains_get_id(tempState);
State.idCount--;
}
returnList.Add(tempState);
}
else
{
State.idCount--;
}
// Third action
tempState = new State(riverBankLeft.getCannibals() - 1, riverBankLeft.getMissionaries() - 1, riverBankRight.getCannibals() + 1, riverBankRight.getMissionaries() + 1, boatIs);
if (tempState.isValidState())
{
if (closedSet.contains_get_id(tempState) != -1)
{
tempState.id = closedSet.contains_get_id(tempState);
State.idCount--;
}
returnList.Add(tempState);
}
else
{
State.idCount--;
}
// Fourth action
tempState = new State(riverBankLeft.getCannibals() - 1, riverBankLeft.getMissionaries() - 0, riverBankRight.getCannibals() + 1, riverBankRight.getMissionaries() + 0, boatIs);
if (tempState.isValidState())
{
if (closedSet.contains_get_id(tempState) != -1)
{
tempState.id = closedSet.contains_get_id(tempState);
State.idCount--;
}
returnList.Add(tempState);
}
else
{
State.idCount--;
}
// Fifth action
tempState = new State(riverBankLeft.getCannibals() - 0, riverBankLeft.getMissionaries() - 1, riverBankRight.getCannibals() + 0, riverBankRight.getMissionaries() + 1, boatIs);
if (tempState.isValidState())
{
if (closedSet.contains_get_id(tempState) != -1)
{
tempState.id = closedSet.contains_get_id(tempState);
State.idCount--;
}
returnList.Add(tempState);
}
else
{
State.idCount--;
}
}
else if (boatIs == RIGHT)
{
// First action
tempState = new State(riverBankLeft.getCannibals() + 2, riverBankLeft.getMissionaries() + 0, riverBankRight.getCannibals() - 2, riverBankRight.getMissionaries() - 0, boatIs);
if (tempState.isValidState())
{
if (closedSet.contains_get_id(tempState) != -1)
{
tempState.id = closedSet.contains_get_id(tempState);
State.idCount--;
}
returnList.Add(tempState);
}
else
{
State.idCount--;
}
// Second action
tempState = new State(riverBankLeft.getCannibals() + 0, riverBankLeft.getMissionaries() + 2, riverBankRight.getCannibals() - 0, riverBankRight.getMissionaries() - 2, boatIs);
if (tempState.isValidState())
{
if (closedSet.contains_get_id(tempState) != -1)
{
tempState.id = closedSet.contains_get_id(tempState);
State.idCount--;
}
returnList.Add(tempState);
}
else
{
State.idCount--;
}
// Third action
tempState = new State(riverBankLeft.getCannibals() + 1, riverBankLeft.getMissionaries() + 1, riverBankRight.getCannibals() - 1, riverBankRight.getMissionaries() - 1, boatIs);
if (tempState.isValidState())
{
if (closedSet.contains_get_id(tempState) != -1)
{
tempState.id = closedSet.contains_get_id(tempState);
State.idCount--;
}
returnList.Add(tempState);
}
else
{
State.idCount--;
}
// Fourth action
tempState = new State(riverBankLeft.getCannibals() + 1, riverBankLeft.getMissionaries() + 0, riverBankRight.getCannibals() - 1, riverBankRight.getMissionaries() - 0, boatIs);
if (tempState.isValidState())
{
if (closedSet.contains_get_id(tempState) != -1)
{
tempState.id = closedSet.contains_get_id(tempState);
State.idCount--;
}
returnList.Add(tempState);
}
else
{
State.idCount--;
}
// Fifth action
tempState = new State(riverBankLeft.getCannibals() + 0, riverBankLeft.getMissionaries() + 1, riverBankRight.getCannibals() - 0, riverBankRight.getMissionaries() - 1, boatIs);
if (tempState.isValidState())
{
if (closedSet.contains_get_id(tempState) != -1)
{
tempState.id = closedSet.contains_get_id(tempState);
State.idCount--;
}
returnList.Add(tempState);
}
else
{
State.idCount--;
}
}
return(returnList);
}
static void Main(string[] args)
{
// For the heuristic function I loosen the problem by disregarding
// the "!cannibals > missionaries" rule and assuming the boat can return on its own
//
// Heuristic Function:
// h(n) = (#MissionariesLeft + #CannibalsLeft) / BoatCapacity
// which equals the optimal number of trips left to right needed to solve the relaxed problem
Log log = new Log();
State InitialState = new State("initial");
log.WriteLine("Initial State created...\n");
State GoalState = new State("goal");
log.WriteLine("Goal State created...\n\n");
Frontier frontier = new Frontier();
ClosedSet closedSet = new ClosedSet();
State currentState = null;
frontier.Add(InitialState);
int step = 1;
while (!frontier.isEmpty())
{
log.Write("Step " + step + ": ");
step++;
// Log frontier and closed set
log.Write(frontier.printFrontier() + " | " + closedSet.printClosedSet() + " | ");
currentState = frontier.Remove();
// Log current state
log.Write(currentState.getID().ToString());
if (closedSet.contains(currentState))
{
// Log '-' for the children list if the closed set contains current state
log.WriteLine(" | - ");
continue;
}
else if (currentState.equals(GoalState))
{
log.Write(" | GOAL STATE");
log.WriteLine("\nSolution found!");
break;
}
string printChildren = " | ";
foreach (State expandingState in currentState.expandState(closedSet))
{
printChildren += expandingState.getID() + ", ";
frontier.Add(expandingState);
}
log.WriteLine(printChildren.TrimEnd().TrimEnd(','));
closedSet.add(currentState);
}
Console.WriteLine("Program executed successfully. Check log for results...");
Console.Read();
}