From 20c93249bb183773e3929a1afc34c11cec8f4803 Mon Sep 17 00:00:00 2001
From: Ben Harris <ben@tilde.team>
Date: Sun, 4 Dec 2022 21:37:27 -0500
Subject: [PATCH] add some ext methods for Range

---
 AOC.Common/Extensions.cs | 21 ++++++++++++++++++++-
 AOC2022/Day04.cs         | 17 +++++++----------
 2 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/AOC.Common/Extensions.cs b/AOC.Common/Extensions.cs
index d0c80cc..f285db8 100644
--- a/AOC.Common/Extensions.cs
+++ b/AOC.Common/Extensions.cs
@@ -58,6 +58,25 @@ public static class Extensions
     public static bool Contains(this Range range, int i) =>
         i >= range.Start.Value && i <= range.End.Value;
 
+    /// <summary>
+    /// Does <paramref name="r1"/> contain the entire range of <paramref name="r2"/>?
+    /// </summary>
+    /// <param name="r1"></param>
+    /// <param name="r2"></param>
+    /// <returns></returns>
+    public static bool Contains(this Range r1, Range r2) =>
+        r1.Start.Value <= r2.Start.Value && r1.End.Value >= r2.End.Value;
+
+    /// <summary>
+    /// Do <paramref name="r1"/> and <paramref name="r2"/> overlap?
+    /// </summary>
+    /// <param name="r1"></param>
+    /// <param name="r2"></param>
+    /// <returns></returns>
+    public static bool Overlaps(this Range r1, Range r2) =>
+        r1.Start.Value <= r2.End.Value && r1.End.Value >= r2.Start.Value &&
+        r2.Start.Value <= r1.End.Value && r2.End.Value >= r1.Start.Value;
+
     /// <summary>
     /// Creates a new BigInteger from a binary (Base2) string
     /// <see href="https://gist.github.com/mjs3339/73042bc0e717f98796ee9fa131e458d4" />
@@ -103,4 +122,4 @@ public static class Extensions
     public static IEnumerable<KeyValuePair<TKey, TValue>> WhereValue<TKey, TValue>(
         this IEnumerable<KeyValuePair<TKey, TValue>> source, Func<TValue, bool> func) =>
         source.Where(pair => func(pair.Value));
-}
+}
\ No newline at end of file
diff --git a/AOC2022/Day04.cs b/AOC2022/Day04.cs
index d686c6c..56cf0c8 100644
--- a/AOC2022/Day04.cs
+++ b/AOC2022/Day04.cs
@@ -5,22 +5,19 @@ namespace AOC2022;
 /// </summary>
 public sealed class Day04 : Day
 {
-    private readonly List<List<int>> _ranges = new();
+    private readonly List<(Range r1, Range r2)> _ranges;
 
     public Day04() : base(2022, 4, "Camp Cleanup")
     {
-        foreach (var line in Input)
-            _ranges.Add(line.Split(',').SelectMany(q => q.Split('-')).Select(int.Parse).ToList());
+        _ranges = Input
+            .Select(line => line.Split(',').SelectMany(q => q.Split('-')).Select(int.Parse).ToList())
+            .Select(p => (new Range(p[0], p[1]), new Range(p[2], p[3])))
+            .ToList();
     }
 
     public override object Part1() =>
-        _ranges.Count(r =>
-            (r[0] >= r[2] && r[0] <= r[3] && r[1] >= r[2] && r[1] <= r[3]) ||
-            (r[2] >= r[0] && r[2] <= r[1] && r[3] >= r[0] && r[3] <= r[1]));
+        _ranges.Count(r => r.r1.Contains(r.r2) || r.r2.Contains(r.r1));
 
     public override object Part2() =>
-        _ranges.Count(r => (r[0] >= r[2] && r[0] <= r[3]) ||
-                           (r[1] >= r[2] && r[1] <= r[3]) ||
-                           (r[2] >= r[0] && r[2] <= r[1]) ||
-                           (r[3] >= r[0] && r[3] <= r[1]));
+        _ranges.Count(r => r.r1.Overlaps(r.r2));
 }
\ No newline at end of file