From 57c026e4e9bcb24f79ef47b8ea20d8fbd0bb437c Mon Sep 17 00:00:00 2001
From: Tim Kurvers <tim@moonsphere.net>
Date: Tue, 3 Dec 2024 22:44:28 +0100
Subject: [PATCH] feat(rust): add solutions for 2024 day 2

---
 rust/src/2024/02.rs                 | 55 +++++++++++++++++++++++++++++
 rust/src/utils/challenges/macros.rs |  2 +-
 2 files changed, 56 insertions(+), 1 deletion(-)
 create mode 100644 rust/src/2024/02.rs

diff --git a/rust/src/2024/02.rs b/rust/src/2024/02.rs
new file mode 100644
index 0000000..a91c265
--- /dev/null
+++ b/rust/src/2024/02.rs
@@ -0,0 +1,55 @@
+use std::ops::Index;
+
+use advent_of_code::utils::challenges::prelude::*;
+
+type Report = Vec<i32>;
+
+fn parse(input: &PuzzleInput) -> Vec<Report> {
+    input.trim().lines().map(|line| {
+        line.split_ascii_whitespace().map(|level| level.parse::<i32>().unwrap()).collect()
+    }).collect()
+}
+
+fn is_safe(report: &Report) -> bool {
+    let mut sign: i32 = 0;
+    for i in 0..report.len() - 1 {
+        let (a, b) = (report.index(i), report.index(i + 1));
+
+        let diff = a - b;
+        let diffabs = diff.abs();
+        if diffabs < 1 || diffabs > 3 { return false }
+
+        let diffsign = diff.signum();
+        if sign != 0 && sign != diffsign { return false }
+        sign = diffsign
+    }
+
+    true
+}
+
+fn is_safe_with_removal(report: &Report) -> bool {
+    for index in 0..report.len() {
+        let mut variation = report.clone();
+        variation.remove(index);
+        if is_safe(&variation) {
+            return true
+        }
+    }
+    false
+}
+
+fn part_one(input: &PuzzleInput, _args: &RawPuzzleArgs) -> Solution {
+    let reports = parse(input);
+
+    let safe = reports.into_iter().filter(is_safe);
+    Answer(safe.count() as u64)
+}
+
+fn part_two(input: &PuzzleInput, _args: &RawPuzzleArgs) -> Solution {
+    let reports = parse(input);
+
+    let safe = reports.into_iter().filter(is_safe_with_removal);
+    Answer(safe.count() as u64)
+}
+
+solve!(part_one, part_two);
diff --git a/rust/src/utils/challenges/macros.rs b/rust/src/utils/challenges/macros.rs
index 1da1602..7509e57 100644
--- a/rust/src/utils/challenges/macros.rs
+++ b/rust/src/utils/challenges/macros.rs
@@ -16,7 +16,7 @@ macro_rules! preload_challenges {
                 01, 02, 03
             )
             2024 (
-                01
+                01, 02
             )
         }
     };