public State Unpush(State state)
{
if (state.calledLifts.Count == 0 || state.calledLifts.Last() != this.target) {
return null;
}
var result = state.Clone();
result.calledLifts.RemoveAt(result.calledLifts.Count - 1);
result.SetNext(state, new Push(this));
return result;
}
public State Push(State state)
{
if (state.calledLifts.Contains(target)) {
return null;
}
var result = state.Clone();
result.calledLifts.Add(target);
result.SetPrevious(state, new Push(this));
return result;
}
public State Unmove(State state)
{
if (this.lift != null && (state.calledLifts.Contains(this.lift))) {
return null;
}
var result = state.Clone();
result.position = from;
if (this.lift != null) {
result.calledLifts.Insert(0, this.lift);
}
result.SetNext(state, new Move(this));
return result;
}
public State Move(State state)
{
if (this.lift != null && (state.calledLifts.Count == 0 || state.calledLifts[0] != this.lift)) {
return null;
}
var result = state.Clone();
result.position = to;
if (this.lift != null) {
result.calledLifts.RemoveAt(0);
}
result.SetPrevious(state, new Move(this));
return result;
}
public State Unmove(State state)
{
if (this.lift != null && (state.calledLifts.Contains(this.lift)))
{
return(null);
}
var result = state.Clone();
result.position = from;
if (this.lift != null)
{
result.calledLifts.Insert(0, this.lift);
}
result.SetNext(state, new Move(this));
return(result);
}
public State Move(State state)
{
if (this.lift != null && (state.calledLifts.Count == 0 || state.calledLifts[0] != this.lift))
{
return(null);
}
var result = state.Clone();
result.position = to;
if (this.lift != null)
{
result.calledLifts.RemoveAt(0);
}
result.SetPrevious(state, new Move(this));
return(result);
}