diff --git a/Cargo.lock b/Cargo.lock
index fb1fc33..ecfc882 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -74,6 +74,7 @@ dependencies = [
  "clap",
  "color-eyre",
  "itertools",
+ "rangemap",
 ]
 
 [[package]]
@@ -297,6 +298,12 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "rangemap"
+version = "1.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "acbbbbea733ec66275512d0b9694f34102e7d5406fdbe2ad8d21b28dce92887c"
+
 [[package]]
 name = "rustc-demangle"
 version = "0.1.26"
diff --git a/Cargo.toml b/Cargo.toml
index 2491122..7f5cdee 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,3 +7,4 @@ edition = "2024"
 clap = { version = "4.5.53", features = ["derive"] }
 color-eyre = "0.6.5"
 itertools = "0.14.0"
+rangemap = "1.7.0"
diff --git a/src/solutions/day_05.rs b/src/solutions/day_05.rs
index e07968a..7e66f5e 100644
--- a/src/solutions/day_05.rs
+++ b/src/solutions/day_05.rs
@@ -1,20 +1,10 @@
-use std::collections::BTreeMap;
+use rangemap::RangeInclusiveSet;
 
 use crate::solution::Solution;
 
-#[derive(Clone, Copy, Debug)]
-struct Range(u64, u64);
-
-impl Range {
-    fn parse(line: &str) -> Self {
-        let (from, to) = line.split_once('-').unwrap();
-        Self(from.parse().unwrap(), to.parse().unwrap())
-    }
-}
-
 #[derive(Debug)]
 pub struct Day05 {
-    ranges: Vec<Range>,
+    ranges: RangeInclusiveSet<u64>,
     ingredients: Vec<u64>,
 }
 
@@ -22,7 +12,13 @@ impl Solution for Day05 {
     fn with_input(input: String) -> Self {
         let (ranges, ingredients) = input.split_once("\n\n").unwrap();
 
-        let ranges = ranges.lines().map(Range::parse).collect();
+        let ranges = ranges
+            .lines()
+            .map(|line| {
+                let (from, to) = line.split_once('-').unwrap();
+                from.parse().unwrap()..=to.parse().unwrap()
+            })
+            .collect();
         let ingredients = ingredients.lines().map(|l| l.parse().unwrap()).collect();
 
         Self {
@@ -32,19 +28,10 @@ impl Solution for Day05 {
     }
 
     fn part1(&self) -> String {
-        let mut ingredients_map = self
-            .ingredients
+        self.ingredients
             .iter()
-            .copied()
-            .map(|i| (i, false))
-            .collect::<BTreeMap<_, _>>();
-
-        for Range(from, to) in &self.ranges {
-            for (_, is_fresh) in ingredients_map.range_mut(from..=to) {
-                *is_fresh = true;
-            }
-        }
-
-        ingredients_map.values().filter(|v| **v).count().to_string()
+            .filter(|i| self.ranges.contains(i))
+            .count()
+            .to_string()
     }
 }