public List <CoinsState> FindMoves(CoinsState state)
{
List <CoinsState> states = new List <CoinsState>();
var one = state.Copy();
one.Parent = state;
one.FirstCoin.ChangeSide();
one.SecondCoin.ChangeSide();
states.Add(one);
var two = state.Copy();
two.Parent = state;
two.FirstCoin.ChangeSide();
two.ThirdCoin.ChangeSide();
states.Add(two);
var three = state.Copy();
three.Parent = state;
three.ThirdCoin.ChangeSide();
three.SecondCoin.ChangeSide();
states.Add(three);
return(states);
}
public CoinsState(Coin first, Coin second, Coin third, CoinsState parent)
{
this.FirstCoin = first;
this.SecondCoin = second;
this.ThirdCoin = third;
this.Parent = parent;
}
public static void FindPath(CoinsState state)
{
Stack <CoinsState> s = new Stack <CoinsState>();
while (true)
{
if (state.Parent != null)
{
s.Push(state);
state = state.Parent;
}
else
{
if (s.Count > 0)
{
var count = s.Count;
Console.WriteLine($"1. {Coin.Side.Eagle}-{Coin.Side.Tails}-{Coin.Side.Eagle}");
for (int i = 0; i < count; i++)
{
Console.WriteLine($"{i+2}. {s.Peek().FirstCoin.UpperSide}-{s.Peek().SecondCoin.UpperSide}-{s.Peek().ThirdCoin.UpperSide}");
s.Pop();
}
return;
}
}
}
}
public CoinsState Copy()
{
CoinsState b = new CoinsState(new Coin(this.FirstCoin.UpperSide), new Coin(this.SecondCoin.UpperSide), new Coin(this.ThirdCoin.UpperSide), this);
return(b);
}
public static void Bms(int beamSize, CoinsState start = null)
{
if (start == null)
{
start = new CoinsState();
}
Func <CoinsState, int> heuristic = ca =>
{
if (ca.FirstCoin.UpperSide == start.FirstCoin.UpperSide && ca.SecondCoin.UpperSide == start.SecondCoin.UpperSide && ca.FirstCoin.UpperSide == start.ThirdCoin.UpperSide)
{
return(1);
}
else
{
return(2);
}
};
List <CoinsState> beam = new List <CoinsState>();
List <CoinsState> set = new List <CoinsState>();
List <CoinsState> visited = new List <CoinsState>();
visited.Add(start);
beam.Add(start);
int step = 0;
while (beam.Count != 0)
{
set.Clear();
foreach (var c0 in beam)
{
++step;
foreach (var child in c0.FindMoves(c0))
{
if (visited.Contains(child))
{
continue;
}
visited.Add(child);
set.Add(child);
if (child.IsSolution())
{
if (step < 3)
{
visited.Remove(child);
}
else
{
Console.WriteLine($"Beam search; beamSize:{beamSize}");
FindPath(child);
return;
}
}
}
}
beam.Clear();
beam.AddRange(set.OrderBy(heuristic).Take(beamSize));
}
Console.WriteLine($"Beam search; Not found; beamSize:{beamSize}");
}