Uploading Days 1-3

day1/Day1.cs

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+namespace AdventOfCode2023;
+
+using System.Text.RegularExpressions;
+
+public class Day1
+{
+    private static int artsyStringToInt(string s)
+    {
+        var matches = Regex.Matches(s, @"[0-9]");
+        var result = -1;
+        if (matches.Count == 1)
+        {
+            result = int.Parse($"{matches[0]}{matches[0]}");
+        }
+        else if (matches.Count > 1)
+        {
+            result = int.Parse($"{matches[0]}{matches[matches.Count - 1]}");
+        }
+        return result;
+    }
+
+    private static bool tryResolveNumericValue(string digit, out int? result)
+    {
+        var nameToDigit = new Dictionary<string, int>() {
+            {"one", 1},
+            {"two", 2},
+            {"three", 3},
+            {"four", 4},
+            {"five", 5},
+            {"six", 6},
+            {"seven", 7},
+            {"eight", 8},
+            {"nine", 9}
+        };
+        var matches = Regex.Matches(digit, @"one|two|three|four|five|six|seven|eight|nine");
+        if (matches.Count > 0)
+        {
+            result = nameToDigit[matches[0].ToString()];
+            return true;
+        }
+        result = null;
+        return false;
+    }
+
+    private static int searchStringForDigit(string s, bool digitReversed = false)
+    {
+        var currentWord = "";
+        foreach (var c in s)
+        {
+            if (Char.IsDigit(c))
+            {
+                return int.Parse(c.ToString());
+            }
+            else if (Char.IsLetter(c))
+            {
+                int? foundDigit;
+                if (digitReversed)
+                {
+                    currentWord = c.ToString() + currentWord;
+                }
+                else
+                {
+                    currentWord = currentWord + c.ToString();
+                }
+                if (tryResolveNumericValue(currentWord, out foundDigit) && foundDigit != null)
+                {
+                    return (int)foundDigit; // VSCode needs a cast here for some reason
+                }
+            }
+        }
+        return -1;
+    }
+
+    private static int artsyStringToIntPartTwo(string s)
+    {
+        var reversedString = new string(s.Reverse().ToArray());
+        return int.Parse($"{searchStringForDigit(s)}{searchStringForDigit(reversedString, true)}");
+    }
+
+    public static int PartOne(IList<string> lines)
+    {
+        return lines.Aggregate(0, (current, line) => current + artsyStringToInt(line));
+    }
+
+    public static int PartTwo(IList<string> lines)
+    {
+        return lines.Aggregate(0, (current, line) => current + artsyStringToIntPartTwo(line));
+    }
+}

day1/Program.cs

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+using AdventOfCode2023;
+
+var fileContents = File.ReadAllText(Path.GetFullPath("input.txt"));
+var lines = fileContents.Split(Environment.NewLine);
+Console.WriteLine($"The answer to Part 1 is {Day1.PartOne(lines)}");
+Console.WriteLine($"The answer to Part 2 is {Day1.PartTwo(lines)}");

day1/day1.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net7.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+</Project>