2024: move to single Rust crate

5 files changed, 164 insertions, 0 deletions

diff --git a/2024_rust/src/day1.rs b/2024_rust/src/day1.rs
new file mode 100644
index 0000000..0b6c13d
--- /dev/null
+++ b/2024_rust/src/day1.rs
@@ -0,0 +1,45 @@
+pub fn p1(input: &str) -> String {
+    let mut left: Vec<u32> = vec![];
+    let mut right: Vec<u32> = vec![];
+    for line in input.lines() {
+        let mut fields = line.split_whitespace();
+        let e = "Wrong file format";
+        left.push(fields.next().expect(e).parse().expect(e));
+        right.push(fields.next().expect(e).parse().expect(e));
+    }
+    left.sort_unstable();
+    right.sort_unstable();
+
+    let mut distance: u32 = 0;
+    for i in 0..left.len() {
+        let l = left[i];
+        let r = right[i];
+        distance += if l >= r { l - r } else { r - l };
+    }
+
+    distance.to_string()
+}
+
+use std::collections::HashMap;
+
+pub fn p2(input: &str) -> String {
+    let mut left: Vec<u32> = vec![];
+    let mut right: HashMap<u32, u32> = HashMap::new();
+    for line in input.lines() {
+        let mut fields = line.split_whitespace();
+        let e = "Wrong file format";
+        left.push(fields.next().expect(e).parse().expect(e));
+        let r: u32 = fields.next().expect(e).parse().expect(e);
+        match right.get(&r) {
+            None => right.insert(r, 1),
+            Some(v) => right.insert(r, v + 1),
+        };
+    }
+
+    let mut distance: u32 = 0;
+    for l in left {
+        distance += l * right.get(&l).unwrap_or(&0);
+    }
+
+    distance.to_string()
+}
diff --git a/2024_rust/src/day2.rs b/2024_rust/src/day2.rs
new file mode 100644
index 0000000..f809141
--- /dev/null
+++ b/2024_rust/src/day2.rs
@@ -0,0 +1,65 @@
+#[derive(PartialEq, Clone, Copy)]
+enum Direction {
+    Up,
+    Down,
+    Unknown,
+}
+use Direction::*;
+
+fn is_safe(levels: &[u32]) -> bool {
+    let mut direction = Unknown;
+    for i in 0..levels.len() - 1 {
+        let [x, y] = levels[i..=i + 1] else {
+            unreachable!()
+        };
+        let (diff, d) = if x > y { (x - y, Down) } else { (y - x, Up) };
+        if direction == Unknown {
+            direction = d;
+        }
+        if diff == 0 || diff > 3 || direction != d {
+            return false;
+        }
+    }
+    return true;
+}
+
+pub fn p1(input: &str) -> String {
+    let mut total = 0;
+    for report in input.lines() {
+        let levels: Vec<u32> = report
+            .split_whitespace()
+            .map(|l| l.parse().unwrap())
+            .collect();
+        if is_safe(&levels) {
+            total += 1;
+        }
+    }
+
+    total.to_string()
+}
+
+fn is_safe_with_dampener(levels: &[u32]) -> bool {
+    for i in 0..levels.len() {
+        let mut levels_without_i: Vec<u32> = levels.to_vec();
+        levels_without_i.remove(i);
+        if is_safe(&levels_without_i) {
+            return true;
+        }
+    }
+    return false;
+}
+
+pub fn p2(input: &str) -> String {
+    let mut total = 0;
+    for report in input.lines() {
+        let levels: Vec<u32> = report
+            .split_whitespace()
+            .map(|l| l.parse().unwrap())
+            .collect();
+        if is_safe(&levels) || is_safe_with_dampener(&levels) {
+            total += 1;
+        }
+    }
+
+    total.to_string()
+}
diff --git a/2024_rust/src/day3.rs b/2024_rust/src/day3.rs
new file mode 100644
index 0000000..cdcd62a
--- /dev/null
+++ b/2024_rust/src/day3.rs
@@ -0,0 +1,33 @@
+use regex::Regex;
+
+pub fn p1(input: &str) -> String {
+    let re = Regex::new(r"mul\(([0-9]{1,3}),([0-9]{1,3})\)").unwrap();
+
+    let mut result: u32 = 0;
+    for (_, [x, y]) in re.captures_iter(input).map(|cs| cs.extract()) {
+        result += x.parse::<u32>().unwrap() * y.parse::<u32>().unwrap();
+    }
+
+    result.to_string()
+}
+
+pub fn p2(input: &str) -> String {
+    let re = Regex::new(r"do\(\)|don't\(\)|mul\(([0-9]{1,3}),([0-9]{1,3})\)").unwrap();
+
+    let mut doing = true;
+    let mut result: u32 = 0;
+    for cs in re.captures_iter(input) {
+        let mut it = cs.iter().flatten().map(|m| m.as_str());
+        match it.next().unwrap() {
+            "do()" => doing = true,
+            "don't()" => doing = false,
+            mul if doing && mul.starts_with("mul") => {
+                let mut next = || it.next().unwrap().parse::<u32>().unwrap();
+                result += next() * next();
+            }
+            _ => (),
+        }
+    }
+
+    result.to_string()
+}
diff --git a/2024_rust/src/dayN.rs b/2024_rust/src/dayN.rs
new file mode 100644
index 0000000..d325291
--- /dev/null
+++ b/2024_rust/src/dayN.rs
@@ -0,0 +1,11 @@
+pub fn p1(input: &str) -> String {
+    let result = "TODO";
+
+    result.to_string()
+}
+
+pub fn p2(input: &str) -> String {
+    let result = "TODO";
+
+    result.to_string()
+}
diff --git a/2024_rust/src/main.rs b/2024_rust/src/main.rs
new file mode 100644
index 0000000..ed94ec2
--- /dev/null
+++ b/2024_rust/src/main.rs
@@ -0,0 +1,10 @@
+mod day3;
+use day3 as current_day;
+const INPUT_FILE: &str = "inputs/3";
+
+fn main() {
+    let input = std::fs::read_to_string(INPUT_FILE).unwrap();
+
+    println!("Result (P1): {}", current_day::p1(&input));
+    println!("Result (P2): {}", current_day::p2(&input));
+}