Advent of Code 2023, Day 3 Solution https://adventofcode.com/2023/day/3

CommonManager.cs

using System;
using System.IO;
using System.Collections;
using System.Collections.Generic;
using System.Net.Mime;
using System.Dynamic;
using System.Linq.Expressions;

namespace Managers
{
    // 521515
    // 69527306

    public static class CommonManager
    {
        #region Objects
        public struct Coordinate
        {
            public Coordinate(char symbol, int x, int y)
            {
                this.Symbol = symbol;
                this.X = x;
                this.Y = y;
            }

            public char Symbol { get; }
            public int X { get; }
            public int Y { get; }
        }

        public class Mapping
        {
            public HashSet<Coordinate> Hash = new HashSet<Coordinate>();
            public char[,] Map;

            public Mapping(int width, int height)
            {
                Map = new char[height, width];
            }
        }
        #endregion

        public static List<string> ReadInput(string filePath = "input.txt")
        {
            List<string> content = new();

            using (var fs = File.Open(filePath, FileMode.Open, FileAccess.Read))
            {
                using (var sr = new StreamReader(fs))
                {
                    string? line;
                    while ((line = sr.ReadLine()) != null)
                    {
                        content.Add(line);
                    }
                }
            }

            return content;
        }

        private static bool _isSymbol(char ch)
        {
            return ch != '.' && !Char.IsDigit(ch);
        }

        public static Mapping Analyze(List<string> content)
        {
            Mapping mapping = new Mapping(content[0].Length, content.Count);

            int x, y = 0;

            // Enumerate each line in the content.
            foreach (var line in content)
            {
                x = 0;

                // Enumerate each character in the line.
                foreach (var ch in line)
                {
                    // If we have a symbol, store it in the hash.
                    if (_isSymbol(ch))
                    {
                        // Store the symbol coordinate.
                        mapping.Hash.Add(new Coordinate(ch, x, y));
                    }

                    // Add the character to the overall map.
                    mapping.Map[y,x] = ch;

                    x++;
                }

                y++;
            }

            return mapping;
        }

        private static int _getNumber(string line, int index)
        {
            // Starting at line[index], find the left-most separator character (or 0-index) and then return the entire value up until the next separator (or end of line).
            if (index >= line.Length)
            {
                return 0;
            }

            int start = index;
            char ch = line[start];
            while (start >= 0 && Char.IsDigit(ch))
            {
                start--;
                if (start > -1)
                {
                    ch = line[start];
                }
            }

            // Start on the number.
            start++;

            // Find the index of the next separator.
            int end = start;
            while (end < line.Length && Char.IsDigit(line[end]))
            {
                end++;
            }

            return Int32.Parse(line.Substring(start, end - start));
        }

        private static string _getLine(char[,] chars, int y)
        {
            // Get the line.
            string line = "";
            for (int x = 0; x < chars.GetLength(0); x++)
            {
                line += chars[y, x];
            }

            return line;
        }

        private static List<int> _findAdjacentNumbers(Mapping mapping, Coordinate item)
        {
            List<int> numbers = new(8) { 0, 0, 0, 0, 0, 0, 0, 0 };

            // Up Left.
            if (item.Y > 0 && item.X > 0 && Char.IsDigit(mapping.Map[item.Y - 1, item.X - 1]))
            {
                // Get the full line.
                string line = _getLine(mapping.Map, item.Y - 1);

                // Extract the adjacent number.
                int number = _getNumber(line, item.X - 1);
                if (number > 0)
                {
                    numbers[0] = number;
                }
            }
            // Up.
            if (item.Y > 0 && Char.IsDigit(mapping.Map[item.Y - 1, item.X]))
            {
                // Get the full line.
                string line = _getLine(mapping.Map, item.Y - 1);

                // Extract the adjacent number.
                int number = _getNumber(line, item.X);
                if (number > 0)
                {
                    numbers[1] = number;
                }
            }
            // Up Right.
            if (item.Y > 0 && item.X < mapping.Map.GetLength(1) - 1 && Char.IsDigit(mapping.Map[item.Y - 1, item.X + 1]))
            {
                // Get the full line.
                string line = _getLine(mapping.Map, item.Y - 1);

                // Extract the adjacent number.
                int number = _getNumber(line, item.X + 1);
                if (number > 0)
                {
                    numbers[2] = number;
                }
            }
            // Right.
            if (item.X < mapping.Map.GetLength(1) - 1 && Char.IsDigit(mapping.Map[item.Y, item.X + 1]))
            {
                // Get the full line.
                string line = _getLine(mapping.Map, item.Y);

                // Extract the adjacent number.
                int number = _getNumber(line, item.X + 1);
                if (number > 0)
                {
                    numbers[3] = number;
                }
            }
            // Down Right.
            if (item.Y < mapping.Map.GetLength(0) - 1 && item.X < mapping.Map.GetLength(1) - 1 && Char.IsDigit(mapping.Map[item.Y + 1, item.X + 1]))
            {
                // Get the full line.
                string line = _getLine(mapping.Map, item.Y + 1);

                // Extract the adjacent number.
                int number = _getNumber(line, item.X + 1);
                if (number > 0)
                {
                    numbers[4] = number;
                }
            }
            // Down.
            if (item.Y < mapping.Map.GetLength(0) - 1 && Char.IsDigit(mapping.Map[item.Y + 1, item.X]))
            {
                // Get the full line.
                string line = _getLine(mapping.Map, item.Y + 1);

                // Extract the adjacent number.
                int number = _getNumber(line, item.X);
                if (number > 0)
                {
                    numbers[5] = number;
                }
            }
            // Down Left.
            if (item.Y < mapping.Map.GetLength(0) - 1 && item.X > 0 && Char.IsDigit(mapping.Map[item.Y + 1, item.X - 1]))
            {
                // Get the full line.
                string line = _getLine(mapping.Map, item.Y + 1);

                // Extract the adjacent number.
                int number = _getNumber(line, item.X - 1);
                if (number > 0)
                {
                    numbers[6] = number;
                }
            }
            // Left.
            if (item.X > 0 && Char.IsDigit(mapping.Map[item.Y, item.X - 1]))
            {
                // Get the full line.
                string line = _getLine(mapping.Map, item.Y);

                // Extract the adjacent number.
                int number = _getNumber(line, item.X - 1);
                if (number > 0)
                {
                    numbers[7] = number;
                }
            }

            // If we have an Up, discard Up-left and Up-Right. If we have a Down, discard Down-Left and Down-Right.
            if (numbers[1] > 0)
            {
                numbers[0] = 0;
                numbers[2] = 0;
            }

            if (numbers[5] > 0)
            {
                numbers[6] = 0;
                numbers[4] = 0;
            }

            return numbers;
        }

        /// <summary>
        /// Find all adjacent numbers to any symbol in the map and return a list for the sum of the values.
        /// </summary>
        /// <param name="mapping">Mapping</param>
        /// <returns>List of int</returns>
        public static List<int> FindAdjacent(Mapping mapping)
        {
            List<int> result = new();

            foreach (var item in mapping.Hash)
            {
                // Find all adjacent numbers to the current symbol.
                List<int> numbers = _findAdjacentNumbers(mapping, item);

                // Sum all numbers.
                result.AddRange(numbers.Where(number => number > 0));
            }

            return result;
        }

        /// <summary>
        /// Find all adjacent numbers to the symbol '*' where there are two or more numbers and return a list for the product of the values.
        /// </summary>
        /// <param name="mapping">Mapping</param>
        /// <returns>List of int</returns>
        public static List<int> FindAdjacentGears(Mapping mapping)
        {
            List<int> result = new();

            foreach (var item in mapping.Hash.Where(item => item.Symbol == '*'))
            {
                // Find all adjacent numbers to the current '*' symbol.
                List<int> numbers = _findAdjacentNumbers(mapping, item);

                // Check if there are at least two values.
                int count = numbers.Where(number => number > 0).Count();
                if (count >= 2)
                {
                    // Multiply the numbers.
                    result.Add(numbers.Where(number => number > 0).Aggregate((a, b) => a * b));
                }
            }

            return result;
        }
    }
}

input.txt

............830..743.......59..955.......663..........................................367...........895....899...............826...220......
.......284.....*............*.....$...+.....*...377..................*.......419.............488...*.......*...................*..-....939..
....%.........976..679.461.7..........350..33.........$.380...$...151.897..........295..#......*....105.....418.............481........&....
...992.....#......=...../........701................508...*..578........................259...331.................795..945........79........
.........868........................*.............................17*..........348................441*852........*.....-...........@.....922
....................*200............311..63................452.......323.#778.*....674....................680......696...372.....*..........
.......266.......209......589.....=......*...365.........7.*...233.............755....*......644...272........697..*....*.....682..225......
..836..........................949....607..........&....*..899...*....679.527.........331..........$....788../.....43....89.................
........367.....328.&......%...............680...69..717.......60.......*.*............................*..........................728...264.
........*.........*..119.253.......................................626....129...274............97...679.......752........*.......*....*.*...
........360......471........../.........573-.702.............866...@...........*......772....../........259....*.........430....136.742.543.
.........................../.852...............*...775...............643....455....../...........832....*.....41..535.......................
.............-..........340.................103....*..........$...51*..................74................438......%...776...+.23*..663......
.15.......806...............990.....................427....924............530.........=..............................*....968.....=....480..
......#..............@914...*..............*........................%......*................................/.....406.................*.....
....201.........79........592............70.894.....247..513+....367..$299.698......199................-.....223....../.........563....783..
......................448........489................*.................................*....440...889...715..........351.....39..............
.138....../766...........*.......................152.........................377....599.......*...*...........................@.............
....%.820.......10*43.670..$87....100*244..@706..........668..319#...........................831.736....@............./..693.....321%.......
......=...930#..................@...................493....*............152......569.................=.914....764.....9.-...................
378$...............&.....854..505.........%........&.....124......12........117.....*591..979..76..133..........+............/..........883.
...............602.141.....*...............770.....................*.........*................../.........874.@....../684....778............
...........................954.....*397.........................394...........614..307*74..457..............+.514.......................327.
........335*25.....-....31..........................................$...719.................*........6..214................878..............
...............86*.269....*...480........................*....140..947....*..&.......................*......972..............*..364*274.....
501-.......805..........285...*..................6....335.167...*........18...332.............741...127......+.............246..............
......616.......752*276.....470.848..599.........*............779..=................539...961..$.........204.......-..201*.....%............
.491.....*..521.........*94.......*.-.....&...163........285/......51..99*......474..*...-.......945.....&......839.......140...201.....$...
....$.795..*........539.........500.......662.............................421....*...459..../.......*407.............../................471.
...........110.......*...............252.............................%..........730......551..509.............824...230....569....48=.......
......150...................................+..70.565=.&320.........983....155................=.....54.......%............*....@......../...
...............972..146...........49.433..137..............................*....%..................@....................436.451..........328
568-...@.552%....-.-................*.................957................93......74...........*........156.566../....#...........285........
.....565..............693....443......................*....394.@58...362...................383.583.............542.38............./..890....
...*.................*........*........&.223...........506.............=..................................300...............477........&....
..612..459..........462....663......125....................720..............355.....253...............904......................*............
........$................................622..............=................*...........*30.........#.$........................284........383
............&.999....&.......................%........240....295*681.846....53.....806......793..646....626./76..737....479.........558.@...
.........892..#.......885.....804..587*....340.........*..............%............*.........*..........*................%............/.....
660..635...........-............./.....213........$....512.....551.............*....910........................@............................
........*..........361..270*.....................328..............*.........853........................*.....985...965............232...948.
..501@......................213...412$.....375..................631..916.......................254...284.........#....*..252........*.......
...................695............................872*876..622..........-.........*..575...851*..................910.395..*....*717.248.....
.....91.........80....*..390...........497....496............*.......@.........297..*................&....873.............946.8.........647.
.......*.424.......108.....=.............*..................686....418.............131........600.96.327...=...561...321............343*....
....731....*..............................938..........256..............909.......................................*.........................
.........811...=....................680...........167...*...601.....................892..#.......142*.......151..108............201.........
................653........879....@.*.........%...*...699..*..............726............695.870.....526.$................*8............234.
....54....311..............=...320..619.......495.375.......926....914.........654..............*........236...$.......444.....@613.........
...*........*......450*............................................*...786.625.......804.850.....674..........305...........................
..593.512....517.......155.....646*239....286......+...........96..264....*......471.*......*.........314*901..............879..............
..........................................=.....419....820......&..................+.......163....148........................*....586.......
.....331.....................637....126.................*..147............650...............................................315....*........
.......%......................$....../.................392....@...943..34...*......752.............................161..30.........970.521..
.........984.412#.......-.569...@................464....................*.275..&.....#.126*506....................*.......=.168-............
.724..................570....*.914.388.........%..$.........274.......263.......130..............102.....2....21+.268....................226
..........776=...6........759.......*..283..309.....682......$..........................................%........................446........
....%284.........-....#...........119....*......622...@....+............/.......929..178...........141/............../650...628.+...........
....................440........88.........335...*.......804............968..976*....+...................$.421..431..................*.......
.....880@.......871.....30......................249...........134....*................*...............95....-...*.....856...353...94.....963
...............*....97..&.......989./.........*.....522+..$.....*.226.436.905......347.396.707...511..........342.....-.....*...........*...
........936*....299.........217.&...478....931.457........62.391............&...............*..../...884*....................370........483.
....965.....992.............*......................................371*771.............37..382...........990...391.......852................
.......*........985.......753.&..........561.204.......................................*......................*...........@..........+935...
......677.....................164.883...............325........951.....847....%......433....*944.50...753..344..............................
.829.......583........429............*34......243...*.........*.............329.%........421...........*..........803..746............675...
...*..................*....512............999.......102......398.................640................401....310.............164...452..*.....
269........9........705....*........782....%.......................615.734....-..............289...........*.....................=....661...
........37.#..............14.......*........../.......586.............*........623.......129........324.....601...%.....@...................
...165................#.........861............463.......*.......361*..............356........175.....*.........906.897..716....118..#......
.....*.............728....417.........+...395#.........443...........829.....390-....................399...............*..........+..813....
....176..253...846......$...........719..........132............897...............334......................20...........51.....%............
..............*....*..278................958........*.......=.................183*.......427.......766.......*..914.282......674............
....&......344...249.....................*.....445.770.....67.....301................295*.........*....715.390...*...../...............424..
.....541......................160.580...........#................=...........*677..............394.......*........327....739...179.360..*...
..........=................%.....*................-954......%.............406......765..................930.....*.........../.....*.....370.
....%.....979.379..........415...............318..........284....440../............-....133.........157......579.550................747.....
.240..........*.....................@...........*642............*.....84.....%.331................2*...................582...=........*.....
......=.....246....167...............704.............763........999.......781...*.....-109............126..801............*.484....632..542.
....%..488.........@..........................$954....*../.....................779..........232................510.....149..................
...27..........984.........*....485.....937........982..234..............225..................*..........122.............................16.
...........473.#..........558..*.............410-...........93............#..655....846....829.....760......=...................=....+......
.....=390..*...................624........#.................+..473..............#......=...........+...577#......$...481.......651.869.806..
747.......543.259.../717............&...346.......948..........$...........472.............230+......=.........206......*...................
................*........+.224/...798.........311...*..896*220...............&.+..................825....../............378...370...........
...............485.641.674.....................*......................618.......389........................565..&674...........*............
..........475.................=.162............461.441...................*..........652......&....508..856...........364....464.............
...............154...452#...693....*................*.......391.........979....344..&.......814..............501.......=....................
...............*................425....25#...........788............879...........*.....29....................&....................850...794
393.............523...507*683..............174@..........-.............=...369....439....-.......*305.891..........952............*.........
..........+...............................................535..911.........................*....1.........441.....-.........88...906........
..........997...17.............779..............960...................209........545......513................*...........98...........+608..
.....................63.968...*.........340.......*...858..339...........%.-767...+...173........47.........906............*210.............
.............&..575..*....@.788.........*.........178.....*.......949.................+...........*.............-.....399.............@.....
..........571....%....984............414...............$.912.....*......302.............594.240..724....341..645.......*.......=..848.642...
....282@...........*......=......189.....138...227*.906.........70......*..................*.............=..........957...657.81../.........
..........*...$.813.179.901.592.....*....................................7....127.............$692...............$..........*.........*.....
.......207..91..............*.....784...872..756.........&..322..............*.........*19.........749.......548..624.694..858...512..598...
.................+.........352...........*.....*.934..126...*.....351..........40...616.......153.....*661............*...........*.........
...823........829...346...........821...826.304...%.......115.......*..........*...............*.............../...622...523.......606......
...*...............*.............*...................186...........813....716@.372....16..300...489..108.....770.......................697..
..........919...782.......912................@.........*.%485............................*..........*...............208.220....853..........
...308......*............*......269.........539.......2.............853.......941.660.532........246.......980..357*....+.....*......./.....
..../......32.164.......15.479.=.............................=...............*....*......................#....*......+......-.855.....415...
.......305..../.....649....*......633...925...634............121............355....578.......14*....422..543.297....429..142................
..960..+..............*.....536......*..@....-.......51..-.........592#..........+..............9..*........................................
.....*......515......434............908..........189......430..................332...722..-.........450..#.........................139......
..259......*.............................39..33.....$..................................*...159..443.....925.............743....414.&...=437.
......58..475...........227%.......217..../...*................../...............&....506..........................63..*.......*............
.......=......-..............993....%.........166........605....293........977+..498......%.....834...455...........*.....%....981.991......
...........636..728...*.......*.......494...............................................205........*.@...........528....226.........#....785
664.9..............$..9...494.272...............725*....775...$....854..........226.243..........832....637*73................165...........
...*...340+.............@...*.......548.............405....*...768..*..............*.......81.........................10.787.$.......918....
.......................145...265....+..........110........45.........90..299.....$........&.....696...475.-452..290....*...*..........@.....
......+....246.108.305...................894....=............121.588......*....69...................................236..97......348........
.......709........*...........-...........-..........411...=...*.......135........................738..383.....634*..........429.@..........
...........%........%217......119.....................@..47.........+.......923..............606...*.......960..............-...............
....835.....744...................546.......215.............512.....950.......%...444......&...$.833......./.........813.......400..%...48..
........362.......898..#.......................*.732........*.............965....&.........584..................521..#...........-.995......
....64.*.........*.....265........781..376...320.#........998...450.......%............................$...............................304..
....-...966...875..981........742*.......*...........*276.........*...............541.....219.279..357..164...551..%717...............%.....
...................*...786.$..........*...163.....915...........960...%...509.135*...........*................-...........%.539.............
....666..699......179..+...612..=734..545...........................88.....&.......392...46..........483=..&.......548.135.....*.413.#620...
...$....*....948..........................530.656....%..484....*..................*......./...741..........444......*.......150...*.........
......................524...928..........=........858....=..562.571........117@.195..896......*......662.......148.388.............320......
...166..48.../....-............#...159.......487.....................260...............#...713.........*.347................................
......*.......657..837.....273.......%........*...155.................*........225..................228.....*370..../.......724.....764.....
......654.679.................@.........-....918...................681..461.............................776......737.................+......
...........*....859......881#............625......$...........888.........+...57...............887.$.......*............................#911
...46*....72...&...................................102.............651........*......*530.......-..667....850..829*.869%........298.........
......925..........892.352*........6.41....................+...160.$.....*.72..878..1.....................................738......*926..32.
...............279.........721......*..............694....799..&......878....*................219....+...482..368$...........*../...........
......604........*....................583*506........-...........740..........347............*....576......*................498..478.974....
..486.-....................626..................320........&....../.................*979.=....863........497........111..............%......
...................................538..78...*.....*......7...455.......223......939......673..........=......559-....*...834............58.
.......644....&.......#..669+.1.......*.....782.....865......*....779..#..............110...../....937..312...........489...................
.......*....571.....69........*.......169...................919....*.....808.................335...*.............................24*896.....
.......233................590.553..............198=..450.........661.......*.....................15...-....................-575.............
...........919*.....................................*.......234.........492..%...........300...........301........./866..........*..........
...............470.....440.874...116....240........299......................27......409.......................................639.136.......

Program.cs

using Managers;

// Read schematic input.
var lines = CommonManager.ReadInput(Path.Combine(Directory.GetCurrentDirectory(), "../../../input.txt"));

// Build a map, including coordinates of the symbols.
var mapping = CommonManager.Analyze(lines);

// Find all numbers that are adjacent to the symbols.
var values = CommonManager.FindAdjacent(mapping);
values.ForEach(Console.WriteLine);

Console.WriteLine(values.Sum());

Console.WriteLine(CommonManager.FindAdjacentGears(mapping).Sum());