Added day 3 solution.

AoC2018/AoC2018.csproj

@@ -12,6 +12,9 @@
     <None Update="Input\Day2Input.txt">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
+    <None Update="Input\Day3Input.txt">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
   </ItemGroup>
 
 </Project>

AoC2018/Solutions/Day3Solution.cs

@@ -0,0 +1,124 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.IO;
+using System.Linq;
+using System.Text.RegularExpressions;
+
+namespace AoC2018.Solutions
+{
+    public class Day3Solution : Solution
+    {
+        public override string Title => "No Matter How You Slice It";
+
+        public override int Day => 3;
+
+        public override void Run()
+        {
+            string[] input = File.ReadAllLines(Path.Combine("Input", "Day3Input.txt"));
+
+            Console.WriteLine($"Part 1: {CalculatePart1(input)}");
+            Console.WriteLine($"Part 2: {CalculatePart2(input)}");
+        }
+
+        public int CalculatePart1(string[] input)
+        {
+            List<Claim> claims = new List<Claim>();
+
+            int maxX = 0, maxY = 0;
+            foreach (var s in input)
+            {
+                var claim = new Claim(s);
+                maxX = Math.Max(maxX, claim.X + claim.Width);
+                maxY = Math.Max(maxY, claim.Y + claim.Height);
+                claims.Add(claim);
+            }
+
+            int[] map = new int[maxX * maxY];
+            foreach (Claim claim in claims)
+            {
+                for (int y = 0; y < claim.Height; y++)
+                for (int x = 0; x < claim.Width; x++)
+                    map[(maxX * (claim.Y + y)) + (claim.X + x)]++;
+            }
+
+            int count = 0;
+            for (int y = 0; y < maxY; y++)
+            {
+                for (int x = 0; x < maxX; x++)
+                {
+                    if (map[y * maxX + x] > 1)
+                        count++;
+                }
+            }
+
+            return count;
+        }
+
+        public int CalculatePart2(string[] input)
+        {
+            List<Claim> claims = new List<Claim>();
+
+            int maxX = 0, maxY = 0;
+            foreach (var s in input)
+            {
+                var claim = new Claim(s);
+                maxX = Math.Max(maxX, claim.X + claim.Width);
+                maxY = Math.Max(maxY, claim.Y + claim.Height);
+                claims.Add(claim);
+            }
+
+            int[] map = new int[maxX * maxY];
+            foreach (Claim claim in claims)
+            {
+                for (int y = 0; y < claim.Height; y++)
+                for (int x = 0; x < claim.Width; x++)
+                    map[(maxX * (claim.Y + y)) + (claim.X + x)]++;
+            }
+
+            foreach (Claim claim in claims)
+            {
+                bool clean = true;
+
+                for (int y = 0; y < claim.Height; y++)
+                for (int x = 0; x < claim.Width; x++)
+                {
+                    if (map[(maxX * (claim.Y + y)) + (claim.X + x)] > 1)
+                        clean = false;
+                }
+
+                if (clean)
+                    return claim.Index;
+            }
+
+            return -1;
+        }
+    }
+
+    public class Claim
+    {
+        public int Index { get; set; }
+        public int X { get; set; }
+        public int Y { get; set; }
+        public int Width { get; set; }
+        public int Height { get; set; }
+
+        public Claim(string line)
+        {
+            Match match = Regex.Match(line, @"#(\d+) @ (\d+),(\d+): (\d+)x(\d+)");
+            if (match.Success)
+            {
+                Index = int.Parse(match.Groups[1].Value);
+                X = int.Parse(match.Groups[2].Value);
+                Y = int.Parse(match.Groups[3].Value);
+                Width = int.Parse(match.Groups[4].Value);
+                Height = int.Parse(match.Groups[5].Value);
+            }
+        }
+
+        public override string ToString()
+        {
+            return $"Index: {Index}, Pos: {X},{Y}, Size: {Width}x{Height}";
+        }
+    }
+}

AoC2018/Solutions/Solution.cs

@@ -8,7 +8,6 @@ namespace AoC2018.Solutions
     {
         public abstract string Title { get; }
         public abstract int Day { get; }
-
         public abstract void Run();
     }
 }