From 8b3bbab954677d4deca879dddd431fc5c1253960 Mon Sep 17 00:00:00 2001
From: Andrew Glaze <andrew.glaze76@gmail.com>
Date: Wed, 20 Dec 2023 09:34:15 -0500
Subject: [PATCH] day18 part1

---
 src/day18.rs | 143 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs   |   1 +
 2 files changed, 144 insertions(+)
 create mode 100644 src/day18.rs

diff --git a/src/day18.rs b/src/day18.rs
new file mode 100644
index 0000000..ba6cb64
--- /dev/null
+++ b/src/day18.rs
@@ -0,0 +1,143 @@
+use aoc_runner_derive::{aoc, aoc_generator};
+use strum_macros::Display;
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+struct Step {
+    dir: Direction,
+    length: i32
+}
+
+#[derive(Debug, Display, PartialEq, Eq, Clone, Copy)]
+enum Direction {
+    Up,
+    Down,
+    Left,
+    Right
+}
+
+impl Direction {
+    fn get_coordinate_modifier(&self) -> (i32, i32) {
+        match self {
+            Direction::Up => (0, 1),
+            Direction::Down => (0, -1),
+            Direction::Left => (-1, 0),
+            Direction::Right => (1, 0),
+        }
+    }
+}
+
+trait DirectionConvertable {
+    fn to_direction(&self) -> Direction;
+}
+
+impl DirectionConvertable for &str {
+    fn to_direction(&self) -> Direction {
+        match *self {
+            "U" => Direction::Up,
+            "D" => Direction::Down,
+            "L" => Direction::Left,
+            "R" => Direction::Right,
+            _ => panic!("Invalid Direction")
+        }
+    }
+}
+
+#[aoc_generator(day18)]
+fn parse(input: &str) -> Vec<Step> {
+    let steps = input.lines()
+        .map(|line| {
+            let mut line = line.split(' ');
+            Step {
+                dir: line.next().unwrap().to_direction(),
+                length: line.next().unwrap().parse::<i32>().unwrap(),
+            }
+        }).collect::<Vec<_>>();
+
+    steps
+}
+
+#[aoc(day18, part1)]
+fn part1(steps: &Vec<Step>) -> i32 {
+    let verticies = get_verticies(steps);
+
+    let mut area = 0;
+
+    for win in verticies.windows(2) {
+        area += win[0].y * win[1].x;
+        area -= win[0].x * win[1].y;
+    }
+
+    // Due to how area works in math, half of the premitier spots are included in the area calculation.
+    (area / 2) + (verticies.len() as i32 / 2) + 1
+}
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+struct Coordinate {
+    x: i32,
+    y: i32
+}
+
+fn get_verticies(steps: &Vec<Step>) -> Vec<Coordinate> {
+    let mut cur_pos = Coordinate{ x: 0, y: 0 };
+    let mut verticies: Vec<Coordinate> = vec![cur_pos.clone()];
+
+    for step in steps {
+        let (x_mod, y_mod) = step.dir.get_coordinate_modifier();
+        for _ in 0..step.length {
+            let new_pos = Coordinate{ 
+                x: cur_pos.x + x_mod,
+                y: cur_pos.y + y_mod,
+            };
+            cur_pos = new_pos.clone();
+            verticies.push(new_pos.clone());
+        }
+    }
+
+    verticies
+}
+
+// #[aoc(day18, part2)]
+// fn part2(steps: &Vec<Step>) -> i32 {
+//     todo!()
+// }
+
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const EX: &str = r"R 6 (#70c710)
+D 5 (#0dc571)
+L 2 (#5713f0)
+D 2 (#d2c081)
+R 2 (#59c680)
+D 2 (#411b91)
+L 5 (#8ceee2)
+U 2 (#caa173)
+L 1 (#1b58a2)
+U 2 (#caa171)
+R 2 (#7807d2)
+U 3 (#a77fa3)
+L 2 (#015232)
+U 2 (#7a21e3)";
+
+const EX_2: &str = r"R 6 (#70c710)
+D 6 (#0dc571)
+L 6 (#5713f0)
+U 6 (#d2c081)";
+
+    #[test]
+    fn part1_example() {
+        assert_eq!(part1(&parse(EX)), 62);
+    }
+
+    #[test]
+    fn part1_example2() {
+        assert_eq!(part1(&parse(EX_2)), 49);
+    }
+
+    // #[test]
+    // fn part2_example() {
+    //     assert_eq!(part2(&parse(EX)), "<RESULT>");
+    // }
+}
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
index e9ec93f..8d5fc18 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,4 @@
+mod day18;
 mod day17;
 mod day16;
 mod day15;