diff --git a/src/bin/day5.rs b/src/bin/day5.rs
new file mode 100644
index 0000000..7cc34b8
--- /dev/null
+++ b/src/bin/day5.rs
@@ -0,0 +1,202 @@
+use std::time::Instant;
+
+use aoc_2025::{load, print_res};
+use bstr::BString;
+
+type Parsed = InventoryState;
+
+struct IdRange {
+    start: u64,
+    end: u64,
+}
+
+impl std::fmt::Debug for IdRange {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}..={}", self.start, self.end)
+    }
+}
+
+#[derive(Debug)]
+pub struct InventoryState {
+    fresh: Vec<IdRange>,
+    avail: Vec<u64>,
+}
+
+#[inline(never)]
+pub fn parsing(input: &BString) -> color_eyre::Result<Parsed> {
+    let Some((fresh, avail)) = str::from_utf8(input)?.split_once("\n\n") else {
+        color_eyre::eyre::bail!("No blank line found");
+    };
+
+    Ok(InventoryState {
+        fresh: fresh
+            .lines()
+            .map(|l| {
+                let Some((start, end)) = l.split_once('-') else {
+                    color_eyre::eyre::bail!("Invalid ID range: {l}");
+                };
+                Ok(IdRange {
+                    start: start.parse()?,
+                    end: end.parse()?,
+                })
+            })
+            .collect::<Result<_, _>>()?,
+        avail: avail
+            .lines()
+            .map(|id| id.parse())
+            .collect::<Result<_, _>>()?,
+    })
+}
+
+#[derive(Debug)]
+struct IntervalSet(Vec<IdRange>);
+
+impl IntervalSet {
+    pub fn new() -> Self {
+        Self(Vec::new())
+    }
+
+    fn insert_at(&mut self, i: usize, range: IdRange) {
+        if i == 0 {
+            if self.0[0].start <= range.end {
+                todo!()
+            } else {
+                self.0.insert(0, range);
+            }
+        } else if i == self.0.len() {
+            if self.0[i - 1].end >= range.start {
+                todo!()
+            } else {
+                self.0.push(range);
+            }
+        } else {
+            // We are in the middle of the array
+            if self.0[i - 1].end >= range.start {
+                // The range overlaps with the previous one
+
+                if range.end <= self.0[i - 1].end {
+                    // The new range is completly contained in the previous one
+                } else {
+                    // The range overlaps with at least the previous one
+                    if range.end >= self.0[i].start {
+                        // Part of the range overlaps the next range
+                        let next = self.0.remove(i);
+
+                        if next.end < range.end {
+                            // The range might overlap with two ranges
+                            todo!()
+                        } else {
+                            // Merge the three ranges together
+                            self.0[i - 1].end = next.end;
+                        }
+                    } else {
+                        // Concatenate this range with the next one
+                        self.0[i - 1].end = range.end;
+                    }
+                }
+            } else if self.0[i].start <= range.end {
+                // The range overlaps with the next one
+
+                self.0[i].start = self.0[i].start.min(range.start);
+
+                if range.end <= self.0[i].end {
+                    // The range does not go further than the end of the next
+                } else {
+                    // We have only inserted up to the end of the next range, insert the
+                    // rest
+                    self.insert(IdRange {
+                        start: self.0[i].end + 1,
+                        end: range.end,
+                    })
+                }
+            } else {
+                // We overlap with neither ranges
+                self.0.insert(i, range)
+            }
+        }
+    }
+
+    pub fn insert(&mut self, range: IdRange) {
+        if self.0.is_empty() {
+            self.0.push(range);
+            return;
+        }
+
+        match self.0.binary_search_by_key(&range.start, |r| r.start) {
+            // Two starts overlap
+            Ok(i) => {
+                if range.end <= self.0[i].end {
+                    // Nothing to do, the range is contained inside the existing one
+                } else {
+                    // Replace the existing range with this new superset
+                    self.0.remove(i);
+                    self.insert(range);
+                }
+            }
+            Err(i) => self.insert_at(i, range),
+        }
+    }
+
+    pub fn contains(&mut self, value: u64) -> bool {
+        self.0
+            .binary_search_by(|r| {
+                if value < r.start {
+                    std::cmp::Ordering::Greater
+                } else if value > r.end {
+                    std::cmp::Ordering::Less
+                } else {
+                    std::cmp::Ordering::Equal
+                }
+            })
+            .is_ok()
+    }
+
+    pub fn length(&self) -> u64 {
+        self.0.iter().map(|r| r.end - r.start + 1).sum()
+    }
+}
+
+#[inline(never)]
+pub fn part1(input: Parsed) {
+    let mut ranges = IntervalSet::new();
+
+    for fresh in input.fresh.into_iter() {
+        ranges.insert(fresh);
+    }
+
+    let fresh = input.avail.iter().filter(|&&v| ranges.contains(v)).count();
+
+    print_res!("Fresh ingredient count: {fresh}");
+}
+
+#[inline(never)]
+pub fn part2(input: Parsed) {
+    let mut ranges = IntervalSet::new();
+
+    for fresh in input.fresh.into_iter() {
+        ranges.insert(fresh);
+    }
+
+    print_res!("Total fresh ingredient count: {}", ranges.length());
+}
+
+pub fn main() -> color_eyre::Result<()> {
+    let context = load()?;
+
+    let start = Instant::now();
+    let parsed = parsing(&context.input)?;
+    let elapsed = humantime::format_duration(start.elapsed());
+
+    let start = Instant::now();
+    if context.part == 1 {
+        part1(parsed);
+    } else {
+        part2(parsed);
+    }
+    let elapsed_part = humantime::format_duration(start.elapsed());
+
+    println!("  Parsing: {elapsed}");
+    println!("  Solving: {elapsed_part}");
+
+    Ok(())
+}