Add Rust day 2

src/day_02/mod.rs

@@ -0,0 +1,2 @@
+pub mod part_1;
+pub mod part_2;

src/day_02/part_1.rs

@@ -0,0 +1,26 @@
+use crate::utils;
+
+pub fn answer(text : &str) -> usize {
+    text.split("\n")
+        .map(parse_line)
+        .filter(is_safe_line)
+        .count()
+}
+
+fn is_safe_line(v : &Vec<i32>) -> bool {
+    let diff : Vec<i32> = v
+        .windows(2)
+        .filter_map(|v| Some(v.get(0)? - v.get(1)?))
+        .collect();
+
+    let all_increasing : bool = diff.iter().all(|&x| x < 0);
+    let all_decreasing : bool = diff.iter().all(|&x| x > 0);
+    let all_bounded_ok : bool = diff.iter().all(|&x| x.abs() <= 3);
+
+    all_bounded_ok && (all_increasing || all_decreasing)
+}
+
+fn parse_line(s : &str) -> Vec<i32> {
+    s.split(" ").filter_map(utils::str_to_i32).collect()
+}
+

src/day_02/part_2.rs

@@ -0,0 +1,43 @@
+use crate::utils;
+
+pub fn answer(text : &str) -> usize {
+    text.split("\n")
+        .map(parse_line)
+        .filter(is_dampened_safe_line)
+        .count()
+}
+
+fn is_dampened_safe_line(v : &Vec<i32>) -> bool {
+    if is_safe_line(v) {
+        return true;
+    }
+
+    for i in 0..v.len() {
+        let mut cv = v.to_vec();
+        cv.remove(i);
+
+        if is_safe_line(&cv) {
+            return true;
+        }
+    }
+
+    false
+}
+
+fn is_safe_line(v : &Vec<i32>) -> bool {
+    let diff : Vec<i32> = v
+        .windows(2)
+        .filter_map(|v| Some(v.get(0)? - v.get(1)?))
+        .collect();
+
+    let all_increasing : bool = diff.iter().all(|&x| x < 0);
+    let all_decreasing : bool = diff.iter().all(|&x| x > 0);
+    let all_bounded_ok : bool = diff.iter().all(|&x| x.abs() <= 3);
+
+    all_bounded_ok && (all_increasing || all_decreasing)
+}
+
+fn parse_line(s : &str) -> Vec<i32> {
+    s.split(" ").filter_map(utils::str_to_i32).collect()
+}
+

src/lib.rs

@@ -1,5 +1,6 @@
 mod utils;
 mod day_01;
+mod day_02;
 
 pub fn day_01() {
     let s : String = utils::read_from_file("inputs/01.txt");
@@ -7,3 +8,8 @@ pub fn day_01() {
     println!("Day 01 part 2: {}", day_01::part_2::answer(s.as_str()));
 }
 
+pub fn day_02() {
+    let s : String = utils::read_from_file("inputs/02.txt");
+    println!("Day 02 part 1: {}", day_02::part_1::answer(s.as_str()));
+    println!("Day 02 part 2: {}", day_02::part_2::answer(s.as_str()));
+}

src/main.rs

@@ -1,3 +1,4 @@
 fn main() {
     aoc_2024::day_01();
+    aoc_2024::day_02();
 }

src/utils/mod.rs

@@ -10,6 +10,10 @@ pub fn read_from_file(name : &str) -> String {
     }
 }
 
+pub fn str_to_i32(s : &str) -> Option<i32> {
+    s.trim().to_string().parse::<i32>().ok()
+}
+    
 pub fn str_to_u32(s : &str) -> Option<u32> {
     s.trim().to_string().parse::<u32>().ok()
 }