clippy

src/day01.rs

@@ -15,10 +15,7 @@ fn part1(input: &str) -> Int {
     l.sort();
     r.sort();
 
-    l.into_iter()
-        .zip(r.into_iter())
-        .map(|(l, r)| (l - r).abs())
-        .sum()
+    l.into_iter().zip(r).map(|(l, r)| (l - r).abs()).sum()
 }
 
 fn part2(input: &str) -> Int {

src/day02.rs

@@ -1,17 +1,71 @@
 use std::fs::read_to_string;
 
+use itertools::Itertools;
+
 pub fn day_main() {
-    let input = read_to_string("input/day01.txt").unwrap();
+    let input = read_to_string("input/day02.txt").unwrap();
     println!("part1: {}", part1(&input));
-    // println!("part2: {}", part2(&input));
+    println!("part2: {}", part2(&input));
 }
 
-type Int = i32;
+fn part1(input: &str) -> usize {
+    input
+        .lines()
+        .map(|line| {
+            line.split_whitespace()
+                .map(|s| s.parse::<i32>().unwrap())
+                .collect_vec()
+        })
+        .filter(|report: &Vec<i32>| is_safe(report))
+        .count()
+}
 
-fn part1(input: &str) -> Int {
-    0
+fn part2(input: &str) -> usize {
+    input
+        .lines()
+        .map(|line| {
+            line.split_whitespace()
+                .map(|s| s.parse::<i32>().unwrap())
+                .collect_vec()
+        })
+        .filter(|report: &Vec<i32>| {
+            (0..report.len()).any(|del| {
+                let without = report
+                    .iter()
+                    .enumerate()
+                    .filter_map(|(i, e)| if del != i { Some(*e) } else { None })
+                    .collect_vec();
+                is_safe(&without)
+            })
+        })
+        .count()
+}
+
+fn is_safe(report: &[i32]) -> bool {
+    let pairs = report
+        .windows(2)
+        .map(|window| window[1] - window[0])
+        .collect_vec();
+    let steepest_slope = pairs.iter().map(|x| x.abs()).max().unwrap();
+    let lowest_slope = pairs.iter().map(|x| x.abs()).min().unwrap();
+    let same_sign = pairs.iter().map(|x| x.signum()).unique().count() == 1;
+
+    steepest_slope <= 3 && lowest_slope >= 1 && same_sign
 }
 
 // fn part2(input: &str) -> Int {
 //     0
 // }
+#[cfg(test)]
+mod test {
+    #[test]
+    fn part1() {
+        let input = r"7 6 4 2 1
+1 2 7 8 9
+9 7 6 2 1
+1 3 2 4 5
+8 6 4 4 1
+1 3 6 7 9";
+        assert_eq!(2, super::part1(input));
+    }
+}

src/main.rs

@@ -1,11 +1,12 @@
 use std::env::args;
 
-use advent_of_rust_2024::day01;
+use advent_of_rust_2024::{day01, day02};
 
 fn main() {
     let day: Option<u8> = args().nth(1).and_then(|a| a.parse().ok());
     match day {
         Some(1) => day01::day_main(),
+        Some(2) => day02::day_main(),
         _ => println!("hi"),
     }
 }