From ba91b53e54ffb562683624955144ea6130517c8a Mon Sep 17 00:00:00 2001
From: Ben Harris <ben@tilde.team>
Date: Wed, 20 Sep 2023 11:34:49 -0400
Subject: [PATCH] 2015 day 16

---
 AOC.Test/Test2015.cs |  1 +
 AOC2015/Day16.cs     | 40 ++++++++++++++++++++++++++++++++++++++--
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/AOC.Test/Test2015.cs b/AOC.Test/Test2015.cs
index b8b5dfe..a730cf5 100644
--- a/AOC.Test/Test2015.cs
+++ b/AOC.Test/Test2015.cs
@@ -21,6 +21,7 @@ public class Test2015
     [DataRow(typeof(Day13), "733", "725")]
     [DataRow(typeof(Day14), "2655", "1059")]
     [DataRow(typeof(Day15), "222870", "117936")]
+    [DataRow(typeof(Day16), "103", "405")]
     public void CheckAllDays(Type dayType, string part1, string part2)
     {
         Common.CheckDay(dayType, part1, part2);
diff --git a/AOC2015/Day16.cs b/AOC2015/Day16.cs
index 2e54214..d361bf9 100644
--- a/AOC2015/Day16.cs
+++ b/AOC2015/Day16.cs
@@ -13,7 +13,43 @@ public sealed class Day16 : Day
     {
     }
 
-    public override object Part1() => "";
+    private IEnumerable<string> Common()
+    {
+        return Input
+            .Select(i => Regex.Replace(i, @": \d\d", ": 9"))
+            .WhereMatch("children: 3")
+            .WhereMatch("samoyeds: 2")
+            .WhereMatch("akitas: 0")
+            .WhereMatch("vizslas: 0")
+            .WhereMatch("cars: 2")
+            .WhereMatch("perfumes: 1");
+    }
 
-    public override object Part2() => "";
+    public override object Part1()
+    {
+        return Common()
+            .WhereMatch("cats: 7")
+            .WhereMatch("trees: 3")
+            .WhereMatch("pomeranians: 3")
+            .WhereMatch("goldfish: 5")
+            .Single()
+            .Split(' ', ':')[1];
+    }
+
+    public override object Part2()
+    {
+        return Common()
+            .WhereMatch("cats: [89]")
+            .WhereMatch("trees: [4-9]")
+            .WhereMatch("pomeranians: [012]")
+            .WhereMatch("goldfish: [0-4]")
+            .Single()
+            .Split(' ', ':')[1];
+    }
 }
+
+public static class Day16Extensions
+{
+    public static IEnumerable<string> WhereMatch(this IEnumerable<string> input, string pattern) =>
+        input.Where(i => !i.Contains(pattern.Split(' ')[0]) || Regex.IsMatch(i, pattern));
+}
\ No newline at end of file