PaintFill

PaintFill

using System;

namespace PaintFill
{
    public class Program
    {
        public static void Main(string[] args)
        {
            Point [,] canvas = { 
                                    {  new Point(0, 0, Color.Red), new Point(0, 1, Color.Red)  },
                                    {  new Point(1, 0, Color.Red), new Point(1, 1, Color.Red)  }, 
                                };
            
            Console.WriteLine("Original canvas:");                    
            display(canvas);
                                
            paintFill(canvas, 0, 1, Color.Green);
            
            Console.WriteLine("Repainted canvas:");
            display(canvas);
        }
        
        static void display(Point[,] canvas) {
            for (int i = 0; i < canvas.GetLength(0); i++) {
                for (int j = 0; j < canvas.GetLength(1); j++) {
                    if (canvas[i, j].Color == Color.Red) {
                        Console.Write("R ");
                    } else {
                        Console.Write("G ");
                    }
                }
                Console.WriteLine();
            }
        }
        
        // Note: Only works if the passed in point does not have the new color
        static bool paintFill(Point[,] canvas, int row, int column, Color newColor) {
                        
            if (row < 0  || 
                row >= canvas.GetLength(0) ||
                column < 0 ||
                column >= canvas.GetLength(1)) {
                    return false;
            }
            
            if (canvas[row, column].Color != newColor) {
                
                canvas[row, column].Color = newColor;
                paintFill(canvas, row - 1, column, newColor);
                paintFill(canvas, row + 1, column, newColor);
                paintFill(canvas, row, column - 1, newColor);
                paintFill(canvas, row, column + 1, newColor);
            } 
           
            return true;
        }
    }
    
    enum Color {
        NoColor,
        Green,
        Red
    };
    
    class Point {
        public Point(int row, int column, Color color) {
            Row = row;
            Column = column;
            Color = color;
        }
       
        public int Row {get; private set;}
        
        public int Column {get; private set;}
        
        public Color Color {get; set;}
    }
}