AdventOfCode/AdventOfCode.Solutions/2023/Day 03/Day03.cs

using AdventOfCode.Core;
using System.Text.RegularExpressions;

namespace AdventOfCode.Solutions._2023
{
    public partial class Day03(InputReader reader) : IChallange
    {
        private InputReader _inputReader = reader;

        private class PartNumber
        {
            public int X { get; set; }

            public int Y { get; set; }

            public string Section { get; set; } = string.Empty;

            public int Length => Section.Length;

            public bool IsDigit() => Section.Length > 1;

            public bool IsPartSymbol() => !IsDigit();

            public List<int> XRange => Enumerable.Range(X, Length).ToList();

            public List<int> XRangeWithSpace => Enumerable.Range(X-1, Length+2).ToList();

            public List<int> YRange => Enumerable.Range(Y - 1, 3).ToList();

            public override string ToString()
            {
                return $"[{Y},{X}] {Section}";
            }
        }

        public async Task<string> GetSolutionPart1()
        {
            List<PartNumber> parts = [];
            int row = 0;
            int total = 0;
            await foreach (string line in _inputReader.ReadAsStringLine())
            {
                MatchCollection matchCollection = FindPartItems().Matches(line);
                parts.AddRange(matchCollection.Select(match => new PartNumber { X = match.Index, Y = row, Section = match.Value }));
                row++;
            }

            List<PartNumber> numbers = parts.Where(p => p.IsDigit()).ToList();
            List<PartNumber> symbols = parts.Where(p => p.IsPartSymbol()).ToList();

            foreach(PartNumber number in numbers)
            { 
                var yfilter = symbols.Where(symbol => number.YRange.Contains(symbol.Y));
                var xfilter = yfilter.Where(symbol => number.XRangeWithSpace.Intersect(symbol.XRange).Any());
                bool isPartNumber = xfilter.Any();
                if(isPartNumber)
                {
                    Console.WriteLine("Adding " + number.ToString());
                    total += int.Parse(number.Section);
                    Console.WriteLine("Total: " + total.ToString());
                }
            }

            //Grid<Node> grid = await _inputReader.ReadToGrid<Node>();
            //int row = 0;
            //
            //await foreach(string line in _inputReader.ReadAsStringLine())
            //{
            //    MatchCollection matchCollection = FindDigits().Matches(line);
            //    
            //    foreach (Match match in matchCollection.Cast<Match>())
            //    {
            //        var section = grid.GetSection(match.Index - 1, row - 1, match.Index + match.Length, row + 1).ToList();
            //        bool isPartNumber = section.Any(n => !(n.Char == '.' || (n.Char >= '0' && n.Char <= '9')));
            //        if (isPartNumber) {
            //            total += int.Parse(match.Value);
            //        }
            //    }
            //
            //    row++;
            //}

            return total.ToString();
        }

        public async Task<string> GetSolutionPart2()
        {
            List<PartNumber> parts = [];
            int row = 0;
            int total = 0;
            await foreach (string line in _inputReader.ReadAsStringLine())
            {
                MatchCollection matchCollection = FindPartItems().Matches(line);
                parts.AddRange(matchCollection.Select(match => new PartNumber { X = match.Index, Y = row, Section = match.Value }));
                row++;
            }

            List<PartNumber> numbers = parts.Where(p => p.IsDigit()).ToList();
            List<PartNumber> gears = parts.Where(p => p.IsPartSymbol() && p.Section == "*").ToList();

            foreach (PartNumber gear in gears)
            {
                // check if there are 2 numbers around
                //List<PartNumber> ratios = GetSection(numbers, gear).ToList();

                //if (ratios.Count != 2)
                //    continue;

                //int totalRatio = int.Parse(ratios[0].Section) * int.Parse(ratios[1].Section);

                //total += totalRatio;
            }

            return total.ToString();
        }

        [GeneratedRegex("(\\d+)", RegexOptions.Compiled)]
        private static partial Regex FindDigits();

        [GeneratedRegex("(\\d+)|([^.])", RegexOptions.Compiled)]
        private static partial Regex FindPartItems();
    }
}