From 67180c098fd25e6a6236555e989c254d9859d692 Mon Sep 17 00:00:00 2001
From: George Thomas <georgefsthomas@gmail.com>
Date: Fri, 5 Dec 2025 15:36:12 +0000
Subject: [PATCH] Solve day 5 part 2

---
 haskell/Puzzles/Day5.hs | 25 ++++++++++++++++++++++---
 outputs/real/5/2        |  1 +
 2 files changed, 23 insertions(+), 3 deletions(-)
 create mode 100644 outputs/real/5/2

diff --git a/haskell/Puzzles/Day5.hs b/haskell/Puzzles/Day5.hs
index f102c20..6a07f97 100644
--- a/haskell/Puzzles/Day5.hs
+++ b/haskell/Puzzles/Day5.hs
@@ -1,9 +1,8 @@
 module Puzzles.Day5 (puzzle) where
 
 import Control.Monad
-import Data.Functor
-import Data.List.Extra
-import Data.Maybe
+import Data.List
+import Data.Ord
 import Data.Text.Lazy qualified as TL
 import Puzzle
 import Text.Megaparsec hiding (some)
@@ -25,6 +24,12 @@ puzzle =
                     . length
                     . filter (flip any ranges . isInRange)
                     $ vals
+            , TL.show
+                . sum
+                . map rangeLength
+                . foldr addInterval []
+                . sortOn (Down . (.lower))
+                . fst
             ]
         , extraTests = mempty
         }
@@ -35,5 +40,19 @@ data Range = Range
     }
     deriving (Eq, Ord, Show)
 
+rangeLength :: Range -> Int
+rangeLength r = r.upper - r.lower + 1
+
 isInRange :: Int -> Range -> Bool
 isInRange n r = n >= r.lower && n <= r.upper
+
+extend :: Int -> Range -> Range
+extend upper r = r{upper = max r.upper upper}
+
+addInterval :: Range -> [Range] -> [Range]
+addInterval new = \case
+    [] -> [new]
+    (r : rs) ->
+        if isInRange new.lower r
+            then extend new.upper r : rs
+            else new : r : rs
diff --git a/outputs/real/5/2 b/outputs/real/5/2
new file mode 100644
index 0000000..1525b0e
--- /dev/null
+++ b/outputs/real/5/2
@@ -0,0 +1 @@
+348548952146313
\ No newline at end of file