1 files changed, 70 insertions, 0 deletions
diff --git a/2023/src/bin/day_6.rs b/2023/src/bin/day_6.rs
new file mode 100644
index 0000000..138843e
--- /dev/null
+++ b/2023/src/bin/day_6.rs
@@ -0,0 +1,70 @@
+use nom::{
+    bytes::complete::tag,
+    character::complete::{line_ending, space1, u64 as nom_u64},
+    combinator::map,
+    multi::separated_list1,
+    sequence::tuple,
+    IResult,
+};
+use std::fs;
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let input = fs::read_to_string("inputs/day_6.txt")?;
+    let parsed = RacePlan::multi_parser(&input).unwrap().1;
+    for plan in parsed {
+        dbg!(&plan.win_count_product());
+    }
+
+    Ok(())
+}
+
+#[derive(Debug)]
+struct RacePlan(Vec<RaceRecord>);
+
+#[derive(Debug)]
+struct RaceRecord {
+    time: u64,
+    distance: u64,
+}
+
+impl RacePlan {
+    fn multi_parser(input: &str) -> IResult<&str, Vec<Self>> {
+        separated_list1(line_ending, RacePlan::parser)(input)
+    }
+
+    fn parser(input: &str) -> IResult<&str, Self> {
+        map(
+            tuple((
+                tag("Time:"),
+                space1,
+                separated_list1(space1, nom_u64),
+                line_ending,
+                tag("Distance:"),
+                space1,
+                separated_list1(space1, nom_u64),
+            )),
+            |(_, _, times, _, _, _, distances)| {
+                RacePlan(
+                    times
+                        .into_iter()
+                        .zip(distances.into_iter())
+                        .map(|(time, distance)| RaceRecord { time, distance })
+                        .collect(),
+                )
+            },
+        )(input)
+    }
+
+    fn win_count_product(&self) -> usize {
+        self.0.iter().map(|r| r.count_wins()).product()
+    }
+}
+
+impl RaceRecord {
+    fn count_wins(&self) -> usize {
+        (1..self.time)
+            .map(|charge_time| charge_time * (self.time - charge_time))
+            .filter(|distance| *distance > self.distance)
+            .count()
+    }
+}