From d47a200ff9bef16b5d0a6258dc0e963b44db366d Mon Sep 17 00:00:00 2001
From: Brian Chu <brianmchu42@gmail.com>
Date: Sat, 3 Dec 2022 21:44:55 -0800
Subject: solution for day 4

---
 solutions/day4.fs | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 solutions/day4.fs

(limited to 'solutions')

diff --git a/solutions/day4.fs b/solutions/day4.fs
new file mode 100644
index 0000000..beb0515
--- /dev/null
+++ b/solutions/day4.fs
@@ -0,0 +1,35 @@
+namespace Solutions
+
+module Day4 =
+    open System.IO
+    open System.Text.RegularExpressions
+
+    type range = {
+        startID: int;
+        endID: int
+    }
+
+    let getRanges input =
+        let matches = Regex.Matches(input, "(\d+)-(\d+),(\d+)-(\d+)") 
+                        |> Seq.head 
+                        |> fun x -> x.Groups 
+                        |> Seq.map (fun x -> x.Value) 
+                        |> List.ofSeq 
+                        |> List.tail
+        assert (Seq.length matches = 4)
+        {startID = int matches[0]; endID = int matches[1]}, {startID = int matches[2]; endID = int matches[3]}
+        
+    let ranges = File.ReadLines("inputs/day4.txt") |> Seq.map getRanges
+
+    let contains (rangeA, rangeB) =
+        (rangeA.startID <= rangeB.startID && rangeA.endID >= rangeB.endID) || (rangeA.startID >= rangeB.startID && rangeA.endID <= rangeB.endID)
+
+    let part1 () = ranges |> Seq.filter contains |> Seq.length
+
+    let overlaps (rangeA, rangeB) =
+        (rangeA.startID >= rangeB.startID && rangeA.startID <= rangeB.endID) ||
+        (rangeA.endID >= rangeB.startID && rangeA.endID <= rangeB.endID)     ||
+        (rangeB.startID >= rangeA.startID && rangeB.startID <= rangeA.endID) ||
+        (rangeB.endID >= rangeA.startID && rangeB.endID <= rangeA.endID)
+    
+    let part2 () = ranges |> Seq.filter overlaps |> Seq.length
\ No newline at end of file
-- 
cgit 1.4.1-2-gfad0