Day 6

2 files changed, 63 insertions, 8 deletions

diff --git a/2023/inputs/day_6.txt b/2023/inputs/day_6.txt
new file mode 100644
index 0000000..0a42c40
--- /dev/null
+++ b/2023/inputs/day_6.txt
@@ -0,0 +1,4 @@
+Time:        45     98     83     73
+Distance:   295   1734   1278   1210
+Time:       45988373
+Distance:   295173412781210
diff --git a/2023/src/bin/day_6.rs b/2023/src/bin/day_6.rs
index b3a610b..138843e 100644
--- a/2023/src/bin/day_6.rs
+++ b/2023/src/bin/day_6.rs
@@ -1,19 +1,70 @@
-use nom::IResult;
+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_2.txt")?;
-    let parsed = Example::parser(&input).unwrap().1;
-    dbg!(&parsed);
+    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 Example;
+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 Example {
-    fn parser(_input: &str) -> IResult<&str, Self> {
-        todo!()
+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()
     }
 }