Discussion on: AoC Day 3: No Matter How You Slice It

[Russ Hammett]

c# again

public class FabricSlicing
    {
        public int GetOverlap(int width, int height, IEnumerable<string> fabricClaims)
        {
            var fabric = GetFabricLayout(width, height, fabricClaims);
            return fabric.GetOverlapArea();
        }

        public IEnumerable<FabricSegments> GetNoOverlap(int width, int height, IEnumerable<string> fabricClaims)
        {
            var fabric = GetFabricLayout(width, height, fabricClaims);
            return fabric.GetNoOverlap();
        }

        protected Fabric GetFabricLayout(int width, int height, IEnumerable<string> fabricClaims)
        {
            var fabric = new Fabric(width, height, PopulateFabricClaims(fabricClaims));

            return fabric;
        }

        protected IEnumerable<FabricSegments> PopulateFabricClaims(IEnumerable<string> fabricClaims)
        {
            List<FabricSegments> fabricSegments = new List<FabricSegments>();

            // #1 @ 1,3: 4x4
            Regex regex = new Regex(@"^#(?<id>\d*)\s@\s(?<x>\d*),(?<y>\d*):\s(?<width>\d*)x(?<height>\d*)$");

            foreach (var claim in fabricClaims)
            {
                var matches = regex.Match(claim);

                fabricSegments.Add(new FabricSegments()
                {
                    ClaimId = int.Parse(matches.Groups["id"].Value),
                    Height = int.Parse(matches.Groups["height"].Value),
                    Width = int.Parse(matches.Groups["width"].Value),
                    StartCoordinateX = int.Parse(matches.Groups["x"].Value),
                    StartCoordinateY = int.Parse(matches.Groups["y"].Value)
                });
            }

            return fabricSegments;
        }
    }

    public class Fabric
    {
        private readonly Point[,] _points;

        public Fabric(int width, int height, IEnumerable<FabricSegments> fabricClaims)
        {
            Width = width;
            Height = height;
            FabricClaims = fabricClaims;

            _points = new Point[Width,Height];

            // Instantiate all the points (is there a better way to do this?)
            for (var row = 0; row < Width; row++)
            {
                for (var column = 0; column < Height; column++)
                {
                    _points[row, column] = new Point();
                }
            }

            PopulatePoints();
        }

        public int Width { get; }
        public int Height { get; }

        public IEnumerable<FabricSegments> FabricClaims { get; }

        public int GetOverlapArea()
        {
            int count = 0;
            for (var row = 0; row < Width; row++)
            {
                for (var column = 0; column < Height; column++)
                {
                    if (_points[row, column].HasOverlap)
                    {
                        count++;
                    }
                }
            }

            return count;
        }

        public IEnumerable<FabricSegments> GetNoOverlap()
        {
            var overlap = GetOverlap();
            return FabricClaims.ToList().Except(overlap);
        }

        private void PopulatePoints()
        {
            foreach (var fabricClaim in FabricClaims)
            {
                for (var width = 0; width < fabricClaim.Width; width++)
                {
                    for (var height = 0; height < fabricClaim.Height; height++)
                    {
                        var point = _points[
                            fabricClaim.StartCoordinateX + width,
                            fabricClaim.StartCoordinateY + height
                        ];

                        point.Occupied.Add(fabricClaim);
                    }
                }
            }
        }

        private IEnumerable<FabricSegments> GetOverlap()
        {
            List<FabricSegments> list = new List<FabricSegments>();

            for (var row = 0; row < Width; row++)
            {
                for (var column = 0; column < Height; column++)
                {
                    var point = _points[row, column];
                    if (point.HasOverlap)
                    {
                        list.AddRange(point.Occupied);
                    }
                }
            }

            return list;
        }
    }

    public class FabricSegments
    {
        public int ClaimId { get; set; }

        public int Width { get; set; }
        public int Height { get; set; }

        public int StartCoordinateX { get; set; }
        public int StartCoordinateY { get; set; }
    }

    public class Point
    {
        public bool IsOccupied => Occupied.Count > 0;
        public bool HasOverlap => Occupied.Count > 1;
        public List<FabricSegments> Occupied { get; set; } = new List<FabricSegments>();
    }

Tests:

public class FabricSlicingTests
    {
        private readonly FabricSlicing _subject = new FabricSlicing();

        private class PopulateFabricClaims_FabricSlicing : FabricSlicing
        {
            public IEnumerable<FabricSegments> GetFabricClaims(
                IEnumerable<string> fabricClaims)
            {
                return PopulateFabricClaims(fabricClaims);
            }
        }

        public static IEnumerable<object[]> SampleData =>
            new List<object[]>()
            {
                new object[]
                {
                    new[]
                    {
                        "#1 @ 1,3: 4x4",
                        "#2 @ 3,1: 4x4",
                        "#3 @ 5,5: 2x2"
                    },
                    8,
                    8,
                    4
                }
            };

        [Theory]
        [MemberData(nameof(SampleData))]
        public void ShouldValidateSample(string[] fabricClaims, int width, int height, int expectedOverlap)
        {
            var result = _subject.GetOverlap(width, height, fabricClaims);

            Assert.Equal(expectedOverlap, result);
        }

        [Theory]
        [MemberData(nameof(SampleData))]
        public void ShouldValidateSampleNoOverlap(string[] fabricClaims, int width, int height, int expectedOverlap)
        {
            var result = _subject.GetNoOverlap(width, height, fabricClaims).ToList();

            Assert.Equal(3, result[0].ClaimId);
        }

        [Fact]
        public void ShouldParseClaimsProperly()
        {
            var claim = "#1 @ 2,3: 4x5";

            var subject = new PopulateFabricClaims_FabricSlicing();
            var result = subject.GetFabricClaims(new[] { claim }).ToList();

            Assert.True(result.Count == 1, nameof(result.Count));
            Assert.True(result[0].ClaimId == 1, nameof(FabricSegments.ClaimId));
            Assert.True(result[0].StartCoordinateX == 2, nameof(FabricSegments.StartCoordinateX));
            Assert.True(result[0].StartCoordinateY == 3, nameof(FabricSegments.StartCoordinateY));
            Assert.True(result[0].Width == 4, nameof(FabricSegments.Width));
            Assert.True(result[0].Height == 5, nameof(FabricSegments.Height));
        }

        [Fact]
        public void DoTheThing()
        {
            var file = Utilities.GetFileContents("./Day3/fabricSlicingData.txt");
            var result = _subject.GetOverlap(1000, 1000, file);

            Assert.Equal(110383, result);
        }

        [Fact]
        public void DoTheThingVersion2()
        {
            var file = Utilities.GetFileContents("./Day3/fabricSlicingData.txt");
            var result = _subject.GetNoOverlap(1000, 1000, file).ToList();

            Assert.Equal(129, result[0].ClaimId);
        }
    }