diff --git a/IDAstar.cs b/IDAstar.cs index 2222969..a02fdd6 100644 --- a/IDAstar.cs +++ b/IDAstar.cs @@ -1,4 +1,9 @@ +using System.Runtime.Versioning; + using System.Collections.ObjectModel; +using System.Collections; + +[assembly: RequiresPreviewFeatures()] namespace IdaStar { @@ -45,6 +50,56 @@ namespace IdaStar public int ManhattanDistance(Point otherPoint) { return Math.Abs(Row - otherPoint.Row) + Math.Abs(Column - otherPoint.Column); } + + [Flags] + public enum NDirections : byte { + N = 0b0000_0001, + E = 0b0000_0010, + S = 0b0000_0100, + W = 0b0000_1000, + NE = 0b0001_0000, + SE = 0b0010_0000, + SW = 0b0100_0000, + NW = 0b1000_0000, + } + + public List GetNeighbours(byte directions = 0b1111) { + List result = new(); + + if ((directions & ((byte)NDirections.N)) > 0) { + result.Add(new(Row - 1, Column)); + } + if ((directions & ((byte)NDirections.E)) > 0) { + result.Add(new(Row, Column + 1)); + } + if ((directions & ((byte)NDirections.S)) > 0) { + result.Add(new(Row + 1, Column)); + } + if ((directions & ((byte)NDirections.W)) > 0) { + result.Add(new(Row, Column - 1)); + } + if ((directions & ((byte)NDirections.NE)) > 0) { + result.Add(new(Row - 1, Column + 1)); + } + if ((directions & ((byte)NDirections.SE)) > 0) { + result.Add(new(Row + 1, Column + 1)); + } + if ((directions & ((byte)NDirections.SW)) > 0) { + result.Add(new(Row + 1, Column - 1)); + } + if ((directions & ((byte)NDirections.NW)) > 0) { + result.Add(new(Row - 1, Column - 1)); + } + + return result; + } + + public bool IsInsideBox(int Height, int Width) => IsInsideBox(new(Height - 1, Width - 1)); + public bool IsInsideBox(Point bottomRight) => IsInsideBox(new(0, 0), bottomRight); + public bool IsInsideBox(Point topLeft, Point bottomRight) { + return topLeft.Row <= Row && topLeft.Column <= Column && + Row <= bottomRight.Row && Column <= bottomRight.Column; + } } public class WorkingBoard { @@ -87,7 +142,7 @@ namespace IdaStar } public void RunIdaStar() => RunIdaStar(0, 1, (p1, p2) => p1.ManhattanDistance(p2)); - public void RunIdaStar(Comp zero, Comp increment, Func heuristic) where Comp: IComparable { + public void RunIdaStar(Num zero, Num increment, Func heuristic) where Num: INumber { // Don't run algorithm on a "dirty" board // "dirty" = the algorithm was already ran before if (_board.Select((row) => row.Where((state) => state == CellState.PATH).Count()).Any((cnt) => cnt > 0)) { @@ -109,12 +164,35 @@ namespace IdaStar Point destinationPoint = findPoint(CellState.DESTINATION); - Comp search(Point current, Comp cost, Comp threshold) { - throw new NotImplementedException(); + Num search(Point current, Num cost, Num threshold) { + var h = heuristic(current, destinationPoint); + if (h == zero) { + return h; + } + var f = cost + h; + if (f > threshold) { + return f; + } + var min = f; + + foreach(var neighbour in current.GetNeighbours()) { + if (!neighbour.IsInsideBox(_board.Count, _board[0].Count)) { + continue; + } + var neighbourF = search(neighbour, cost + increment, threshold); + if (neighbourF < min) { + min = neighbourF; + } + if (min == zero) { + break; + } + } + + return min; } var threshold = heuristic(startPoint, destinationPoint); - while (threshold.CompareTo(zero) == 0) { + while (threshold == zero) { threshold = search(startPoint, zero, threshold); } } diff --git a/IDAstar.csproj b/IDAstar.csproj index 74abf5c..8b4f2a5 100644 --- a/IDAstar.csproj +++ b/IDAstar.csproj @@ -3,8 +3,13 @@ Exe net6.0 + preview enable enable + + + +