feat: day 2

inputs/day02/example.txt

@@ -0,0 +1,6 @@
+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

src/day01.rs

@@ -1,32 +1,31 @@
-pub fn pt1(input: &str) -> i32 {
+pub fn pt1(input: &str) -> usize {
     let elems = input
         .lines()
         .filter_map(|l| l.split_once("   "))
-        .map(|(l, r)| (l.parse::<i32>(), r.parse::<i32>()))
+        .map(|(l, r)| (l.parse::<usize>(), r.parse::<usize>()))
         .filter(|(l, r)| l.is_ok() && r.is_ok())
         .map(|(l, r)| (l.unwrap(), r.unwrap()));
     let mut lefts = elems.clone().map(|(l, _)| l).collect::<Vec<_>>();
     let mut rights = elems.map(|(_, r)| r).collect::<Vec<_>>();
     lefts.sort_unstable();
     rights.sort_unstable();
-    let res: u32 = lefts
+    lefts
         .iter()
         .zip(rights.iter())
         .map(|(l, r)| l.abs_diff(*r))
-        .sum();
-    res as i32
+        .sum()
 }
-pub fn pt2(input: &str) -> i32 {
+pub fn pt2(input: &str) -> usize {
     let elems = input
         .lines()
         .filter_map(|l| l.split_once("   "))
-        .map(|(l, r)| (l.parse::<i32>(), r.parse::<i32>()))
+        .map(|(l, r)| (l.parse::<usize>(), r.parse::<usize>()))
         .filter(|(l, r)| l.is_ok() && r.is_ok())
         .map(|(l, r)| (l.unwrap(), r.unwrap()));
     let lefts = elems.clone().map(|(l, _)| l);
     let rights = elems.map(|(_, r)| r).collect::<Vec<_>>();
     lefts
-        .map(|l| rights.clone().iter().filter(|r| **r == l).count() as i32 * l)
+        .map(|l| rights.clone().iter().filter(|r| **r == l).count() * l)
         .sum()
 }
 

src/day02.rs

@@ -0,0 +1,64 @@
+use std::cmp::Ordering;
+
+pub fn pt1(input: &str) -> usize {
+    input
+        .lines()
+        .map(|l| {
+            l.split_whitespace()
+                .map(|s| s.parse::<i32>().unwrap())
+                .collect::<Vec<_>>()
+        })
+        .filter(|v| is_safe(v))
+        .count()
+}
+pub fn is_safe(it: &[i32]) -> bool {
+    assert!((it.len() >= 2), "Not enough elements");
+    let first = it.first().unwrap();
+    let second = it[1];
+    match first.cmp(&second) {
+        Ordering::Less => it.windows(2).map(|w| w[1] - w[0]).all(|e| e > 0 && e <= 3),
+        Ordering::Equal => false,
+        Ordering::Greater => it.windows(2).map(|w| w[0] - w[1]).all(|e| e > 0 && e <= 3),
+    }
+}
+
+pub fn is_safe_skipping_one(it: &[i32]) -> bool {
+    is_safe(it)
+        || (0..it.len()).any(|index_to_skip| {
+            let mut to_test = it.to_owned();
+            to_test.remove(index_to_skip);
+            is_safe(&to_test)
+        })
+}
+pub fn pt2(input: &str) -> usize {
+    input
+        .lines()
+        .map(|l| {
+            l.split_whitespace()
+                .map(|s| s.parse::<i32>().unwrap())
+                .collect::<Vec<_>>()
+        })
+        .filter(|v| is_safe_skipping_one(v))
+        .count()
+}
+
+#[cfg(test)]
+mod tests {
+    use std::fs::read_to_string;
+
+    use crate::day02::{pt1, pt2};
+
+    #[test]
+    pub fn test_pt1() {
+        let input =
+            read_to_string("./inputs/day02/example.txt").expect("Missing example.txt for day02");
+        assert_eq!(pt1(&input), 2)
+    }
+    #[test]
+    pub fn test_pt2() {
+        let input =
+            read_to_string("./inputs/day02/example.txt").expect("Missing example.txt for day02");
+
+        assert_eq!(pt2(&input), 4)
+    }
+}

src/main.rs

@@ -1,11 +1,14 @@
 use std::fs::read_to_string;
 
-use crate::day01::{pt1, pt2};
-
 mod day01;
+mod day02;
 fn main() {
     println!("day 01!");
     let input = read_to_string("./inputs/day01/input.txt").expect("Missing input.txt for day01");
-    println!("And the result is: {}", pt1(&input));
-    println!("Part 2: {}", pt2(&input));
+    println!("And the result is: {}", day01::pt1(&input));
+    println!("Part 2: {}", day01::pt2(&input));
+    println!("day 02!");
+    let input = read_to_string("./inputs/day02/input.txt").expect("Missing input.txt for day02");
+    println!("And the result is: {}", day02::pt1(&input));
+    println!("Part 2: {}", day02::pt2(&input));
 }