public static IState bfs(IState start, IState end)
{
Queue <IState> found = new Queue <IState>();
Queue <IState> visited = new Queue <IState>();
IState temp = new IState(start.leftPriests, start.leftDevils, start.rightPriests, start.rightDevils, start.boat, null);
found.Enqueue(temp);
while (found.Count > 0)
{
temp = found.Peek();
if (temp == end)
{
//Debug.Log("solution path:\n");
while (temp.parent != start)
{
temp = temp.parent;
}
return(temp);
}
found.Dequeue();
visited.Enqueue(temp);
// next node
if (temp.boat)
{
// one move to right
if (temp.leftPriests > 0)
{
IState next = new IState(temp);
next.parent = new IState(temp);
next.boat = false;
next.leftPriests--;
next.rightPriests++;
if (next.valid() && !visited.Contains(next) && !found.Contains(next))
{
found.Enqueue(next);
}
}
if (temp.leftDevils > 0)
{
IState next = new IState(temp);
next.parent = new IState(temp);
next.boat = false;
next.leftDevils--;
next.rightDevils++;
if (next.valid() && !visited.Contains(next) && !found.Contains(next))
{
found.Enqueue(next);
}
}
// two moves to right
if (temp.leftDevils > 0 && temp.leftDevils > 0)
{
IState next = new IState(temp);
next.parent = new IState(temp);
next.boat = false;
next.leftPriests--;
next.leftDevils--;
next.rightPriests++;
next.rightDevils++;
if (next.valid() && !visited.Contains(next) && !found.Contains(next))
{
found.Enqueue(next);
}
}
if (temp.leftDevils > 1)
{
IState next = new IState(temp);
next.parent = new IState(temp);
next.boat = false;
next.leftDevils -= 2;
next.rightDevils += 2;
if (next.valid() && !visited.Contains(next) && !found.Contains(next))
{
found.Enqueue(next);
}
}
if (temp.leftPriests > 1)
{
IState next = new IState(temp);
next.parent = new IState(temp);
next.boat = false;
next.leftPriests -= 2;
next.rightPriests += 2;
next.parent = new IState(temp);
if (next.valid() && !visited.Contains(next) && !found.Contains(next))
{
found.Enqueue(next);
}
}
}
else
{
//one move to left
if (temp.rightPriests > 0)
{
IState next = new IState(temp);
next.parent = new IState(temp);
next.boat = true;
next.rightPriests--;
next.leftPriests++;
if (next.valid() && !visited.Contains(next) && !found.Contains(next))
{
found.Enqueue(next);
}
}
if (temp.rightDevils > 0)
{
IState next = new IState(temp);
next.parent = new IState(temp);
next.boat = true;
next.rightDevils--;
next.leftDevils++;
if (next.valid() && !visited.Contains(next) && !found.Contains(next))
{
found.Enqueue(next);
}
}
//two moves to left
if (temp.rightDevils > 0 && temp.rightDevils > 0)
{
IState next = new IState(temp);
next.parent = new IState(temp);
next.boat = true;
next.rightPriests--;
next.rightDevils--;
next.leftPriests++;
next.leftDevils++;
if (next.valid() && !visited.Contains(next) && !found.Contains(next))
{
found.Enqueue(next);
}
}
if (temp.rightDevils > 1)
{
IState next = new IState(temp);
next.parent = new IState(temp);
next.boat = true;
next.rightDevils -= 2;
next.leftDevils += 2;
if (next.valid() && !visited.Contains(next) && !found.Contains(next))
{
found.Enqueue(next);
}
}
if (temp.rightPriests > 1)
{
IState next = new IState(temp);
next.parent = new IState(temp);
next.boat = true;
next.rightPriests -= 2;
next.leftPriests += 2;
if (next.valid() && !visited.Contains(next) && !found.Contains(next))
{
found.Enqueue(next);
}
}
}
}
return(null);
}
public IState(int leftPriests, int leftDevils, int rightPriests, int rightDevils, bool boat, IState parent)
{
this.leftPriests = leftPriests;
this.leftDevils = leftDevils;
this.rightPriests = rightPriests;
this.rightDevils = rightDevils;
this.boat = boat;
this.parent = parent;
}