Day 2

Author: clechasseur

.aocf/config

@@ -1,4 +1,4 @@
 year = 2024
-day = 1
+day = 2
 editor = "vim"
 pager = "less"

src/day_02.rs

@@ -0,0 +1,49 @@
+use itertools::Itertools;
+
+use crate::helpers::input::safe_get_input_as_vecs;
+
+pub fn part_1() -> String {
+    input().into_iter().filter(|v| safe(v)).count().to_string()
+}
+
+pub fn part_2() -> String {
+    input()
+        .into_iter()
+        .filter(|v| dampened(v).iter().any(|v| safe(v)))
+        .count()
+        .to_string()
+}
+
+fn input() -> Vec<Vec<i64>> {
+    safe_get_input_as_vecs(2024, 2)
+}
+
+fn example_input() -> Vec<Vec<i64>> {
+    vec![
+        vec![7, 6, 4, 2, 1],
+        vec![1, 2, 7, 8, 9],
+        vec![9, 7, 6, 2, 1],
+        vec![1, 3, 2, 4, 5],
+        vec![8, 6, 4, 4, 1],
+        vec![1, 3, 6, 7, 9],
+    ]
+}
+
+fn safe(levels: &[i64]) -> bool {
+    let signum = (levels[0] - levels[1]).signum();
+    levels.iter().tuple_windows().all(|(&a, &b)| {
+        let new_diff = a - b;
+        new_diff.signum() == signum && (1i64..=3).contains(&new_diff.abs())
+    })
+}
+
+#[allow(clippy::ptr_arg)]
+fn dampened(levels: &Vec<i64>) -> Vec<Vec<i64>> {
+    (0..levels.len())
+        .map(|i| {
+            let mut dampened = levels.clone();
+            dampened.remove(i);
+            dampened
+        })
+        .collect()
+}

src/helpers/input.rs

@@ -113,6 +113,33 @@ impl Input {
     {
         self.into_pairs().unwrap()
     }
+
+    pub fn into_vecs<T>(self) -> Result<Vec<Vec<T>>, anyhow::Error>
+    where
+        T: FromStr,
+        <T as FromStr>::Err: std::fmt::Debug,
+    {
+        String::try_from(self)?
+            .lines()
+            .map(|line| {
+                line.split_ascii_whitespace()
+                    .map(|value| {
+                        value
+                            .parse()
+                            .map_err(|e| anyhow::anyhow!("failed to parse \"{line}\": {e:?}"))
+                    })
+                    .collect()
+            })
+            .collect()
+    }
+
+    pub fn safe_into_vecs<T>(self) -> Vec<Vec<T>>
+    where
+        T: FromStr,
+        <T as FromStr>::Err: std::fmt::Debug,
+    {
+        self.into_vecs().unwrap()
+    }
 }
 
 impl TryFrom<Input> for String {
@@ -150,3 +177,11 @@ where
 {
     Input::year(year).day(day).safe_get().safe_into_pairs()
 }
+
+pub fn safe_get_input_as_vecs<T>(year: i32, day: u32) -> Vec<Vec<T>>
+where
+    T: FromStr,
+    <T as FromStr>::Err: std::fmt::Debug,
+{
+    Input::year(year).day(day).safe_get().safe_into_vecs()
+}

src/lib.rs

@@ -3,7 +3,8 @@
 #![allow(dead_code)]
 
 pub mod day_01;
+pub mod day_02;
 #[macro_use]
 pub(crate) mod helpers;
 
-build_runner_for_days!(01);
+build_runner_for_days!(01, 02);

src/main.rs

@@ -49,7 +49,7 @@ struct Cli {
 
 fn parse_day(day: &str) -> Result<u32, String> {
     let day = day.parse().map_err(|e| format!("{e:?}"))?;
-    if (1..(RUNNERS.len() as u32)).contains(&day) {
+    if (1..=(RUNNERS.len() as u32)).contains(&day) {
         Ok(day)
     } else {
         Err(format!("{day} is not in 1..={}", RUNNERS.len()))