public static List <RecRateResult> recRate(State2048 root, int depth)
{
List <StateTrans> moves = root.getAllMoveStates();
//If we can't move, the game is over; worst penalty
if (moves.Count == 0)
{
return new List <RecRateResult> {
new RecRateResult(double.MaxValue, MoveDir.Self)
}
}
;
//If the depth is zero, return the result from this state
if (depth == 0)
{
return new List <RecRateResult> {
new RecRateResult(root.rate(), MoveDir.Self)
}
}
;
List <RecRateResult> result = new List <RecRateResult>();
foreach (StateTrans st in moves)
{
double bestOfWorst = double.MaxValue;
List <State2048> allRandom = st.state.getAllRandom();
foreach (State2048 rand in allRandom)
{
List <RecRateResult> randRes = recRate(rand, depth - 1);
//Take the maximum penalty
double worstRate = randRes[0].rating;
for (int i = 1; i < randRes.Count; i++)
{
if (randRes[i].rating > worstRate)
{
worstRate = randRes[i].rating;
}
}
if (worstRate < bestOfWorst)
{
bestOfWorst = worstRate;
}
}
result.Add(new RecRateResult(bestOfWorst, st.dir));
}
return(result);
}
//Copy constructor
public State2048(State2048 s)
{
this.rows = s.rows;
this.cols = s.cols;
this.grid = new int[rows, cols];
for (int r = 0; r < this.rows; r++)
{
for (int c = 0; c < this.cols; c++)
{
this.grid[r, c] = s.grid[r, c];
}
}
}
public static double alphabetarate(State2048 root, int depth, double alpha, double beta, bool player)
{
if (depth == 0)
{
return(root.rate());
}
if (player)
{
List <StateTrans> moves = root.getAllMoveStates();
//If we can't move, the game is over; worst penalty
if (moves.Count == 0)
{
return(double.MaxValue);
}
foreach (StateTrans st in moves)
{
alpha = Math.Min(alpha, alphabetarate(st.state, depth - 1, alpha, beta, !player));
if (beta >= alpha)
{
break;
}
}
return(alpha);
}
else
{
List <State2048> moves = root.getAllRandom();
foreach (State2048 st in moves)
{
beta = Math.Max(beta, alphabetarate(st, depth - 1, alpha, beta, !player));
if (beta <= alpha)
{
break;
}
}
return(beta);
}
}
public List <State2048> getAllRandom()
{
List <State2048> res = new List <State2048>();
List <Tuple <int, int> > free = this.getFree();
foreach (Tuple <int, int> x in free)
{
State2048 next;
next = new State2048(this);
next.grid[x.Item1, x.Item2] = 1;
res.Add(next);
next = new State2048(this);
next.grid[x.Item1, x.Item2] = 2;
res.Add(next);
}
return(res);
}
public bool equalTo(State2048 alt)
{
if (this.rows != alt.rows)
{
return(false);
}
if (this.cols != alt.cols)
{
return(false);
}
for (int r = 0; r < rows; r++)
{
for (int c = 0; c < cols; c++)
{
if (this.grid[r, c] != alt.grid[r, c])
{
return(false);
}
}
}
return(true);
}
public List <StateTrans> getAllMoveStates()
{
List <StateTrans> allMoves = new List <StateTrans>();
State2048 next;
next = new State2048(this);
next.pushLeft();
if (!this.equalTo(next))
{
allMoves.Add(new StateTrans(next, MoveDir.Left));
}
next = new State2048(this);
next.pushRight();
if (!this.equalTo(next))
{
allMoves.Add(new StateTrans(next, MoveDir.Right));
}
next = new State2048(this);
next.pushUp();
if (!this.equalTo(next))
{
allMoves.Add(new StateTrans(next, MoveDir.Up));
}
next = new State2048(this);
next.pushDown();
if (!this.equalTo(next))
{
allMoves.Add(new StateTrans(next, MoveDir.Down));
}
return(allMoves);
}
public StateTrans(State2048 state, MoveDir dir)
{
this.dir = dir;
this.state = state;
}