y2025d1

y2025/src/bin/d1.rs

@@ -0,0 +1,27 @@
+use std::{fs, time::Instant};
+
+use utils::time::get_elapsed_string;
+use y2025::days::d1;
+
+fn main() {
+    let now = Instant::now();
+    println!("Part 1:");
+    part1();
+    println!("Ran in {}", get_elapsed_string(now.elapsed()));
+    let now = Instant::now();
+    println!("Part 2:");
+    part2();
+    println!("Ran in {}", get_elapsed_string(now.elapsed()));
+}
+
+fn part1() {
+    let root = env!("CARGO_MANIFEST_DIR");
+    let content = fs::read_to_string(format!("{root}/resources/1_input.txt")).unwrap();
+    println!("{}", d1::process_part1(&content));
+}
+
+fn part2() {
+    let root = env!("CARGO_MANIFEST_DIR");
+    let content = fs::read_to_string(format!("{root}/resources/1_input.txt")).unwrap();
+    println!("{}", d1::process_part2(&content));
+}

y2025/src/days/d1.rs

@@ -0,0 +1,95 @@
+pub fn process_part1(input: &str) -> i32 {
+    let mut current = 50;
+    let mut zeroes = 0;
+    for line in input.lines() {
+        let (direction, distance) = line.split_at(1);
+        let distance = distance.parse::<i32>().unwrap() % 100;
+        match direction {
+            "L" => current -= distance,
+            "R" => current += distance,
+            _ => panic!("Invalid direction"),
+        };
+        if current < 0 {
+            current += 100;
+        } else if current > 99 {
+            current -= 100;
+        }
+        if current == 0 {
+            zeroes += 1;
+        }
+    }
+    return zeroes;
+}
+
+pub fn process_part2(input: &str) -> i32 {
+    let mut current = 50;
+    let mut zeroes = 0;
+    for line in input.lines() {
+        let is_zero = current == 0;
+        let (direction, distance) = line.split_at(1);
+        let distance = distance.parse::<i32>().unwrap();
+        let mut rotations = {
+            if direction == "L" {
+                if current - distance < 0 && !is_zero {
+                    (current - distance).abs() / 100 + 1
+                } else if current - distance < 0 && is_zero {
+                    (current - distance).abs() / 100
+                } else {
+                    0
+                }
+            } else {
+                if current + distance > 99 {
+                    (current + distance) / 100
+                } else {
+                    0
+                }
+            }
+        };
+        match direction {
+            "L" => current -= distance % 100,
+            "R" => current += distance % 100,
+            _ => panic!("Invalid direction"),
+        };
+        if current < 0 {
+            current += 100;
+        } else if current > 99 {
+            current -= 100;
+        }
+        if current == 0 {
+            zeroes += 1;
+            if rotations > 0 {
+                rotations -= 1;
+            }
+        }
+        zeroes += rotations;
+    }
+    return zeroes;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const INPUT: &str = "L68
+L30
+R48
+L5
+R60
+L55
+L1
+L99
+R14
+L82";
+
+    #[test]
+    fn part1() {
+        let result = process_part1(INPUT);
+        assert_eq!(result, 3);
+    }
+
+    #[test]
+    fn part2() {
+        let result = process_part2(INPUT);
+        assert_eq!(result, 6);
+    }
+}

y2025/src/days/mod.rs

@@ -0,0 +1 @@
+pub mod d1;

y2025/src/lib.rs

@@ -0,0 +1 @@
+pub mod days;