C#
(via LINQPad, in "C# Program" mode; )
Going to have to apply Equitable Stroke Control, as far as any golfing might go, but this is my approach in C# (well, LINQPad, but who wants all the boilerplate that goes into making a full C# app work?).
Grid definitions are variable, with a number of vertical pipes and height of overall structure, and are repeatably-random by passing a seed (see the PipeGrid constructor).
In the absence of a definitive answer as to which way the object would flow if either direction was possible, I have allowed you to specify a behaviour from a number of options (see SolveBehavior enumeration / PipeSolver constructor).
Starting vertical is definable (see PipeSolver.Solve).
I have assumed that the horizontal pipes are always between two adjacent vertical pipes, i.e. no horizontal can bypass a horizontal pipe.
///<summary>Entry point</summary>
void Main()
{
var grid = new PipeGrid(vertical:10, height:10, seed:5);
var solver = new PipeSolver(grid, SolveBehavior.FlipFlop);
solver.Solve(start:2);
}
///<summary>Represents the direction the object is travelling</summary>
enum Direction
{
Down = 0,
Left = 1,
Right = 2
}
///<summary>Determines the route to take if a junction yields both horizontal directions</summary>
enum SolveBehavior
{
///<summary>Throws an <see cref="InvalidOperationException" /></summary>
Fail = 0,
///<summary>Prefers the left-most direction (screen-relative)</summary>
FavorLeft = 1,
///<summary>Prefers the right-most direction (screen-relative)</summary>
FavorRight = 2,
///<summary>Alternates preferred direction, based on the number of turns</summary>
FlipFlop = 3,
///<summary>Prefers the same direction the object travelled, on its last horizontal movement</summary>
SameDirection = 4,
///<summary>Prefers the opposite direction the object travelled, on its last horizontal movement</summary>
Uturn = 5
}
///<summary>Provides the logic for solving a <see cref="PipeGrid" /></summmary>
class PipeSolver
{
///<summary>Creates a new <see cref="PipeSolver" /> for the supplied <paramref name="grid" />,
///with the given <paramref name="behavior" /> used to resolve junctions with both horizontal
///paths</summary>
public PipeSolver(PipeGrid grid, SolveBehavior behavior = SolveBehavior.FlipFlop)
{
if (grid == null) throw new ArgumentNullException("grid");
_grid = grid;
_behavior = behavior;
}
private readonly PipeGrid _grid;
private readonly SolveBehavior _behavior;
///<summary>Simulate the dropping of an object to run through the grid, at the top of a
///given <paramref name="start" /> vertical pipe</summary>
public void Solve(int start = 1, bool dumpFrames = false, string tag = "Result")
{
if (start < 1) start = 1;
if (start > _grid.Verticals) start = _grid.Verticals;
int x, y;
Direction?[,] path = new Direction?[_grid.Width, _grid.Height];
x = (start - 1) * 2;
y = 0;
Direction dir = Direction.Down, lastDir = Direction.Down;
int turns = 0;
do
{
path[x, y] = dir; // we moved through this pipe
// rule 1: when moving through horizontal pipe, object will go down when possible
if ((dir == Direction.Left || dir == Direction.Right) && (x % 2 == 0))
{
lastDir = dir;
dir = Direction.Down;
++turns;
}
// rule 2: when moving through start pipe, object will turn into horizontal pipe when possible
else if (dir == Direction.Down)
{
bool hasLeft = (x > 0 && _grid[x - 1, y]);
bool hasRight = (x < _grid.Width - 1 && _grid[x + 1, y]);
if (hasLeft && hasRight)
{
switch (_behavior)
{
case SolveBehavior.FavorLeft:
hasRight = false; // "forget" about right pipe
break;
case SolveBehavior.FavorRight:
hasLeft = false; // "forget" about left pipe
break;
case SolveBehavior.FlipFlop:
if (turns % 2 == 0) hasLeft = false;
else hasRight = false; // "forget" about left on the even moves, or right on the odd moves
break;
case SolveBehavior.SameDirection: // force staying in the same direction
if (lastDir == Direction.Left) hasRight = false;
else if (lastDir == Direction.Right) hasLeft = false;
else goto case SolveBehavior.FlipFlop; // use the flip-flop behaviour to determine first turn
break;
case SolveBehavior.Uturn: // force turning back on itself
if (lastDir == Direction.Left) hasLeft = false;
else if (lastDir == Direction.Right) hasRight = false;
else goto case SolveBehavior.FlipFlop; // use the flip-flop behaviour to determine first turn
break;
default: throw new InvalidOperationException(
"Failed to find distinct path, with no resolving behavior defined"
);
}
}
if (hasLeft) dir = Direction.Left;
else if (hasRight) dir = Direction.Right;
if (hasLeft || hasRight) ++turns;
}
switch (dir) // update position, based on current direction
{
case Direction.Left: if (x > 0) --x; break;
case Direction.Right: if (x < _grid.Width - 1) ++x; break;
default: ++y; break;
}
if (dumpFrames)
{
DumpFrame(path, start, tag:string.Concat("Frame #", turns, " (", _grid.Seed, ")"));
DrawFrame(path, start, tag:string.Concat("Frame #", turns));
}
}
while (y < _grid.Height);
int end = (x / 2) + 1;
DumpFrame(path, start, end, turns, tag);
DrawFrame(path, start, end, turns, tag);
}
///<summary>Internal method for drawing a given frame</summary>
private void DumpFrame(Direction?[,] path, int start, int? end = null, int? turns = null, string tag = null)
{
var builder = new StringBuilder();
builder.Append(' ', --start * 5).AppendLine("v");
for (int y = 0; y < _grid.Height; y++)
{
for (int x = 0; x < _grid.Width; x++)
{
builder.Append(
(x % 2 == 0)
? path[x, y].HasValue ? ":" : _grid[x, y] ? "|" : " "
: path[x, y].HasValue ? "====" : _grid[x, y] ? "----" : " "
);
}
builder.AppendLine();
}
if (end.HasValue) builder.Append(' ', (end.Value - 1) * 5).AppendLine("^");
if (turns.HasValue) builder.Append(turns.Value)
.Append(" turns were taken to get to ")
.AppendLine(end.HasValue ? "the end." : "this point.");
builder.ToString().Dump(string.IsNullOrWhiteSpace(tag) ? "Frame" : tag);
}
///<summary>Internal method for rendering a frame as a bitmap</summary>
private void DrawFrame(Direction?[,] path, int start, int? end = null, int? turns = null, string tag = null)
{
using (var sprites = new Sprites())
using (var canvas = new Bitmap(16 * _grid.Width, 16 * (_grid.Height + 3)))
using (var graphics = Graphics.FromImage(canvas))
{
graphics.FillRectangle(Brushes.Green, 0, 16, 16 * _grid.Width, 16 * _grid.Height);
_grid.Draw(graphics, sprites, offsetX:0, offsetY:16);
// draw the start position
start = (start - 1) * 32;
graphics.DrawImageUnscaled(sprites.RoadVertical, start, 0);
graphics.DrawImageUnscaled(sprites.CarVertical, start, 0);
graphics.DrawImageUnscaled(sprites.StartFlag, start, 0);
// draw the path
for (int y = 0; y < _grid.Height; y++)
for (int x = 0; x < _grid.Width; x++)
{
if (path[x, y].HasValue)
{
Image car;
switch (path[x, y])
{
case Direction.Left:
// if even, then on a vertical, so turning left; otherwise travelling left
car = (x % 2 == 0) ? sprites.CarTurnLeft : sprites.CarLeft;
break;
case Direction.Right:
// if even, then on a vertical, so turning right; otherwise travelling right
car = (x % 2 == 0) ? sprites.CarTurnRight: sprites.CarRight;
break;
default:
car = sprites.CarVertical;
if (x == 0 && path[x + 1, y].HasValue) // far-left and will move right = turn-right
car = sprites.CarTurnRight;
else if (x == _grid.Width - 1 && path[x - 1, y].HasValue) // far-right and will move left = turn-left
car = sprites.CarTurnLeft;
else if (x > 0 && x < _grid.Width - 1)
{
car = sprites.CarVertical; // if not right or left, then down
if (path[x + 1, y].HasValue && !path[x - 1, y].HasValue) // if came from the left, then turn right
car = sprites.CarTurnRight;
else if (path[x - 1, y].HasValue && !path[x + 1, y].HasValue) // if came from the right, then turn left
car = sprites.CarTurnLeft;
}
break;
}
graphics.DrawImageUnscaled(car, 16 * x, 16 * (y + 1));
}
}
// draw the end position, if we are at the end
if (end.HasValue)
{
end = (end - 1) * 32;
graphics.DrawImageUnscaled(sprites.RoadVertical, end.Value, 16 * (_grid.Height + 1));
graphics.DrawImageUnscaled(sprites.CarVertical, end.Value, 16 * (_grid.Height + 1));
graphics.DrawImageUnscaled(sprites.EndFlag, end.Value, 16 * (_grid.Height + 1));
}
if (turns.HasValue)
{
string s = string.Concat(turns.Value, " turns were taken to get to ",
end.HasValue ? "the end." : "this point.");
graphics.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAliasGridFit;
graphics.DrawString(s, SystemFonts.DefaultFont, Brushes.Black, 0, 16 * (_grid.Height + 2));
}
canvas.Dump(tag ?? "Bonus");
}
}
}
///<summary>Represents a configuration of pipes</summary>
class PipeGrid
{
///<summary>Creates a new <see cref="PipeGrid" />, of a given <paramref name="height" />
///with the given number of <paramref name="vertical" /> pipes, and randomly distributes
///horizontal pipes between them, based on a repeatable <paramref name="seed" />.</summary>
public PipeGrid(int vertical = 4, int height = 8, int? seed = null)
{
if (vertical < 2) vertical = 2;
if (height < 2) height = 2;
Width = (2 * vertical) - 1;
Height = height;
Verticals = vertical;
Seed = seed ?? Environment.TickCount;
var rnd = new Random(Seed);
_nodes = new bool[Width,Height];
for (int x = 0, xw = Width; x < xw; x++)
for (int y = 0; y < height; y++)
{
// place verticals in every even column, and randomly place horizontals in odd columns
if (x % 2 == 0 || rnd.Next(0, 2) == 1)
_nodes[x, y] = true;
}
}
private readonly bool[,] _nodes;
public int Width { get; private set; }
public int Height { get; private set; }
public int Verticals { get; private set; }
public int Seed { get; private set; }
public bool this[int x, int y] { get { return _nodes[x, y]; } }
///<summary>Renders the grid to the LINQPad results pane, for inspection</summary>
public PipeGrid Dump(string tag = null)
{
var builder = new StringBuilder();
for (int y = 0; y < Height; y++)
{
for (int x = 0; x < Width; x++)
{
builder.Append(
(x % 2 == 0)
? _nodes[x, y] ? "|" : " "
: _nodes[x, y] ? "----" : " "
);
}
builder.AppendLine();
}
builder.ToString().Dump(string.IsNullOrWhiteSpace(tag) ? "Grid" : tag);
return this;
}
///<summary>Render the grid as a bitmap image</summary>
public void Draw(Graphics g, Sprites s, int offsetX = 0, int offsetY = 0)
{
for (int y = 0; y < Height; y++)
{
for (int x = 0; x < Width; x++)
{
if (_nodes[x, y])
{
Image sprite = sprite = s.RoadVertical;
if (x % 2 != 0)
sprite = s.RoadHorizontal;
else if (x == 0 && _nodes[1, y])
sprite = s.JunctionTeeRight;
else if (x == Width - 1 && _nodes[x - 1, y])
sprite = s.JunctionTeeLeft;
else if (x > 0 && x < Width - 1)
{
if (_nodes[x - 1, y] && _nodes[x + 1, y])
sprite = s.JunctionCross;
else if (_nodes[x + 1, y] && !_nodes[x - 1, y])
sprite = s.JunctionTeeRight;
else if (_nodes[x - 1, y] && !_nodes[x + 1, y])
sprite = s.JunctionTeeLeft;
}
g.DrawImageUnscaled(sprite,
x:(16 * x) + offsetX,
y:(16 * y) + offsetY);
}
}
}
}
///<summary>Creates a <see cref="PipeGrid" /> with horizontal pipes at all possible positions</summary>
public static PipeGrid CreateAllOpen(int verticals = 4, int height = 8)
{
var grid = new PipeGrid(verticals, height, 0);
for (int y = 0; y < height; y++)
for (int x = 0, xw = grid.Width; x < xw; x++)
grid._nodes[x, y] = true;
return grid;
}
}
///<summary>Store tile sprites, to be used in the graphical rendering of the result</summary>
class Sprites : IDisposable
{
public Sprites()
{
byte[,] car = new byte[,] {
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 3, 3, 3, 3, 3, 3, 3, 3, 0, 0, 0, 0 },
{ 0, 0, 0, 1, 3, 3, 3, 3, 3, 3, 3, 3, 1, 0, 0, 0 },
{ 0, 0, 0, 1, 3, 1, 1, 1, 1, 1, 1, 3, 1, 0, 0, 0 },
{ 0, 0, 0, 1, 3, 1, 1, 1, 1, 1, 1, 3, 1, 0, 0, 0 },
{ 0, 0, 0, 0, 3, 3, 3, 3, 3, 3, 3, 3, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 3, 3, 3, 3, 3, 3, 3, 3, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 3, 3, 3, 3, 3, 3, 3, 3, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 3, 1, 1, 1, 1, 1, 1, 3, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 3, 1, 1, 1, 1, 1, 1, 3, 0, 0, 0, 0 },
{ 0, 0, 0, 1, 3, 1, 1, 1, 1, 1, 1, 3, 1, 0, 0, 0 },
{ 0, 0, 0, 1, 3, 3, 3, 3, 3, 3, 3, 3, 1, 0, 0, 0 },
{ 0, 0, 0, 1, 3, 3, 3, 3, 3, 3, 3, 3, 1, 0, 0, 0 },
{ 0, 0, 0, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 0, 0, 0 },
{ 0, 0, 0, 0, 3, 3, 3, 3, 3, 3, 3, 3, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
};
byte[,] road = new byte[,] {
{ 0, 6, 2, 2, 2, 2, 2, 6, 6, 2, 2, 2, 2, 2, 6, 0 },
{ 0, 6, 2, 2, 2, 2, 2, 6, 6, 2, 2, 2, 2, 2, 6, 0 },
{ 0, 6, 2, 2, 2, 2, 2, 6, 6, 2, 2, 2, 2, 2, 6, 0 },
{ 0, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 0 },
{ 0, 6, 2, 2, 2, 2, 2, 6, 6, 2, 2, 2, 2, 2, 6, 0 },
{ 0, 6, 2, 2, 2, 2, 2, 6, 6, 2, 2, 2, 2, 2, 6, 0 },
{ 0, 6, 2, 2, 2, 2, 2, 6, 6, 2, 2, 2, 2, 2, 6, 0 },
{ 0, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 0 },
{ 0, 6, 2, 2, 2, 2, 2, 6, 6, 2, 2, 2, 2, 2, 6, 0 },
{ 0, 6, 2, 2, 2, 2, 2, 6, 6, 2, 2, 2, 2, 2, 6, 0 },
{ 0, 6, 2, 2, 2, 2, 2, 6, 6, 2, 2, 2, 2, 2, 6, 0 },
{ 0, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 0 },
{ 0, 6, 2, 2, 2, 2, 2, 6, 6, 2, 2, 2, 2, 2, 6, 0 },
{ 0, 6, 2, 2, 2, 2, 2, 6, 6, 2, 2, 2, 2, 2, 6, 0 },
{ 0, 6, 2, 2, 2, 2, 2, 6, 6, 2, 2, 2, 2, 2, 6, 0 },
{ 0, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 0 },
};
byte[,] roadNESW = new byte[,] {
{ 0, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 0 },
{ 6, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 6 },
{ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 },
{ 2, 2, 2, 5, 2, 2, 5, 2, 2, 5, 2, 2, 5, 2, 2, 2 },
{ 2, 2, 2, 2, 5, 5, 2, 5, 5, 2, 5, 5, 2, 2, 2, 2 },
{ 2, 2, 2, 2, 5, 5, 2, 5, 5, 2, 5, 5, 2, 2, 2, 2 },
{ 2, 2, 2, 5, 2, 2, 5, 2, 2, 5, 2, 2, 5, 2, 2, 2 },
{ 2, 2, 2, 2, 5, 5, 2, 5, 5, 2, 5, 5, 2, 2, 2, 2 },
{ 2, 2, 2, 2, 5, 5, 2, 5, 5, 2, 5, 5, 2, 2, 2, 2 },
{ 2, 2, 2, 5, 2, 2, 5, 2, 2, 5, 2, 2, 5, 2, 2, 2 },
{ 2, 2, 2, 2, 5, 5, 2, 5, 5, 2, 5, 5, 2, 2, 2, 2 },
{ 2, 2, 2, 2, 5, 5, 2, 5, 5, 2, 5, 5, 2, 2, 2, 2 },
{ 2, 2, 2, 5, 2, 2, 5, 2, 2, 5, 2, 2, 5, 2, 2, 2 },
{ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 },
{ 6, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 6 },
{ 0, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 0 },
};
byte[,] roadNES = new byte[,] {
{ 0, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 0 },
{ 0, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 6 },
{ 0, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 },
{ 0, 6, 2, 5, 2, 2, 5, 2, 2, 5, 2, 2, 5, 2, 2, 2 },
{ 0, 6, 2, 2, 5, 5, 2, 5, 5, 2, 5, 5, 2, 2, 2, 2 },
{ 0, 6, 2, 2, 5, 5, 2, 5, 5, 2, 5, 5, 2, 2, 2, 2 },
{ 0, 6, 2, 5, 2, 2, 5, 2, 2, 5, 2, 2, 5, 2, 2, 2 },
{ 0, 6, 2, 2, 5, 5, 2, 5, 5, 2, 5, 5, 2, 2, 2, 2 },
{ 0, 6, 2, 2, 5, 5, 2, 5, 5, 2, 5, 5, 2, 2, 2, 2 },
{ 0, 6, 2, 5, 2, 2, 5, 2, 2, 5, 2, 2, 5, 2, 2, 2 },
{ 0, 6, 2, 2, 5, 5, 2, 5, 5, 2, 5, 5, 2, 2, 2, 2 },
{ 0, 6, 2, 2, 5, 5, 2, 5, 5, 2, 5, 5, 2, 2, 2, 2 },
{ 0, 6, 2, 5, 2, 2, 5, 2, 2, 5, 2, 2, 5, 2, 2, 2 },
{ 0, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 },
{ 0, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 6 },
{ 0, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 0 },
};
byte[,] start = new byte[,] {
{ 0, 0, 1, 1, 1, 0, 4, 4, 4, 0, 0, 0, 4, 0, 0, 0 },
{ 0, 0, 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 0, 0, 0 },
{ 0, 0, 1, 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 0, 0, 0 },
{ 0, 0, 1, 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 0, 0, 0 },
{ 0, 0, 1, 1, 4, 4, 4, 4, 4, 4, 4, 4, 4, 0, 0, 0 },
{ 0, 0, 1, 1, 4, 4, 4, 4, 4, 4, 4, 4, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 4, 4, 4, 4, 4, 4, 4, 4, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 4, 4, 4, 4, 4, 4, 4, 4, 0, 0, 0, 0 },
{ 0, 0, 1, 4, 4, 4, 0, 0, 0, 4, 4, 4, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
};
byte[,] end = new byte[,] {
{ 0, 0, 1, 1, 1, 0, 1, 1, 6, 0, 0, 0, 6, 0, 0, 0 },
{ 0, 0, 1, 6, 6, 6, 1, 1, 6, 6, 1, 1, 6, 0, 0, 0 },
{ 0, 0, 1, 1, 6, 6, 6, 6, 1, 6, 1, 1, 1, 0, 0, 0 },
{ 0, 0, 1, 1, 1, 1, 6, 6, 1, 1, 6, 6, 1, 0, 0, 0 },
{ 0, 0, 1, 1, 1, 1, 1, 1, 6, 1, 6, 6, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 6, 6, 1, 1, 6, 6, 1, 1, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 6, 6, 6, 6, 1, 6, 1, 1, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 1, 1, 6, 6, 1, 1, 6, 6, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 6, 6, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
};
RoadVertical = Sprite(road);
RoadHorizontal = RotateSprite(RoadVertical, 90);
JunctionCross = Sprite(roadNESW);
JunctionTeeRight = Sprite(roadNES);
JunctionTeeLeft = FlipSprite(JunctionTeeRight, horizontal:true);
CarVertical = Sprite(car);
CarLeft = RotateSprite(CarVertical, 90);
CarRight = FlipSprite(CarLeft, horizontal:true);
CarTurnLeft = RotateSprite(CarVertical, 45);
CarTurnRight = FlipSprite(CarTurnLeft, horizontal:true);
StartFlag = Sprite(start);
EndFlag = Sprite(end);
}
public Image RoadVertical { get; private set; }
public Image RoadHorizontal { get; private set; }
public Image JunctionCross { get; private set; }
public Image JunctionTeeLeft { get; private set; }
public Image JunctionTeeRight { get; private set; }
public Image CarVertical { get; private set; }
public Image CarLeft { get; private set; }
public Image CarRight { get; private set; }
public Image CarTurnLeft { get; private set; }
public Image CarTurnRight { get; private set; }
public Image StartFlag { get; private set; }
public Image EndFlag { get; private set; }
///<summary>Create a sprite from the byte data</summary>
private Image Sprite(byte[,] data)
{
int width = data.GetLength(0);
int height = data.GetLength(1);
var image = new Bitmap(width, height);
for (int y = 0; y < height; y++)
for (int x = 0; x < width; x++)
{
Color c;
switch (data[y,x])
{
case 1: c = Color.Black; break;
case 2: c = Color.DarkGray; break;
case 3: c = Color.Red; break;
case 4: c = Color.LimeGreen; break;
case 5: c = Color.Yellow; break;
case 6: c = Color.White; break;
default: continue;
}
image.SetPixel(x, y, c);
}
return image;
}
///<summary>Rotate an image by a number of <paramref name="degrees" /> around the centre</summary>
private Image RotateSprite(Image source, float deg)
{
var b = new Bitmap(source.Width, source.Height);
using (var g = Graphics.FromImage(b))
{
float tx = (float)source.Width / 2.0f;
float ty = (float)source.Height / 2.0f;
g.TranslateTransform(tx, ty);
g.RotateTransform(deg);
g.TranslateTransform(-tx, -ty);
g.DrawImageUnscaled(source, 0, 0);
}
return b;
}
///<summary>Flip an image about its centre</summary>
private Image FlipSprite(Image source, bool horizontal = false, bool vertical = false)
{
var b = new Bitmap(source);
RotateFlipType rft = ( horizontal && vertical) ? RotateFlipType.RotateNoneFlipXY
: ( horizontal && !vertical) ? RotateFlipType.RotateNoneFlipX
: (!horizontal && vertical) ? RotateFlipType.RotateNoneFlipY
: RotateFlipType.RotateNoneFlipNone;
b.RotateFlip(rft);
return b;
}
#region IDisposable implementation
public void Dispose() { Dispose(true); }
~Sprites() { Dispose(false); }
protected void Dispose(bool disposing)
{
if (disposing)
{
GC.SuppressFinalize(this);
using (RoadVertical) { }
using (RoadHorizontal) { }
using (JunctionCross) { }
using (JunctionTeeLeft) { }
using (JunctionTeeRight) { }
using (CarVertical) { }
using (CarLeft) { }
using (CarRight) { }
using (CarTurnLeft) { }
using (CarTurnRight) { }
using (StartFlag) { }
using (EndFlag) { };
}
RoadVertical = null;
RoadHorizontal = null;
JunctionCross = null;
JunctionTeeLeft = null;
JunctionTeeRight = null;
CarVertical = null;
CarLeft = null;
CarRight = null;
CarTurnLeft = null;
CarTurnRight = null;
StartFlag = null;
EndFlag = null;
}
#endregion
}
Update:
Fearing my plain old text output might be a little drab for this popularity context, I offer up an extended version that also draws the path taken as an image. I've modelled it as car, driving through a horrible road network, trying to get to the bottom, but with the world's-worst GPS that forces you to make a turn at every junction.
As a bonus, this also makes it clearer to see the 'turns'.
Enjoy -- vroom vroom!!
Example results:
(verticals: 10, height: 10, random seed:5, start pipe: 2, solve behaviour: FlipFlop})
