Day 14

Cargo.toml

@@ -14,3 +14,11 @@ path = "day12/part1.rs"
 [[bin]]
 name = "d12p2"
 path = "day12/part2.rs"
+
+[[bin]]
+name = "d14p1"
+path = "day14/part1.rs"
+
+[[bin]]
+name = "d14p2"
+path = "day14/part2.rs"

day14/part1.rs

@@ -0,0 +1,54 @@
+use std::ops::Range;
+
+const INPUT: &str = include_str!("input.txt");
+const GRID_WIDTH: i64 = 101;
+const GRID_HEIGHT: i64 = 103;
+const SECONDS: i64 = 100;
+
+const QUADRANT_1: (Range<i64>, Range<i64>) = (0..(GRID_WIDTH/2), 0..(GRID_HEIGHT/2));
+const QUADRANT_2: (Range<i64>, Range<i64>) = ((GRID_WIDTH/2 + 1)..GRID_WIDTH, 0..(GRID_HEIGHT/2));
+const QUADRANT_3: (Range<i64>, Range<i64>) = ((GRID_WIDTH/2 + 1)..GRID_WIDTH, (GRID_HEIGHT/2 + 1)..GRID_HEIGHT);
+const QUADRANT_4: (Range<i64>, Range<i64>) = (0..(GRID_WIDTH/2), (GRID_HEIGHT/2 + 1)..GRID_HEIGHT);
+
+#[derive(Debug)]
+pub struct Robot {
+    pub position: (i64, i64),
+    pub velocity: (i64, i64),
+}
+
+fn main() {
+    let robots = INPUT
+        .lines()
+        .map(|l| l.split_once(" v=").unwrap())
+        .map(|(p, v)| {
+            (
+                p.trim_start_matches("p=").split_once(",").unwrap(),
+                v.split_once(",").unwrap(),
+            )
+        })
+        .map(|(p, v)| Robot {
+            position: (p.0.parse().unwrap(), p.1.parse().unwrap()),
+            velocity: (v.0.parse().unwrap(), v.1.parse().unwrap()),
+        });
+    
+    let mut quadrants = (0u64, 0u64, 0u64, 0u64);
+
+    for mut robot in robots {
+        robot.position = (
+            ((robot.position.0 + robot.velocity.0 * SECONDS)).rem_euclid(GRID_WIDTH),
+            ((robot.position.1 + robot.velocity.1 * SECONDS)).rem_euclid(GRID_HEIGHT),
+        );
+        
+        if QUADRANT_1.0.contains(&robot.position.0) && QUADRANT_1.1.contains(&robot.position.1) {
+            quadrants.0 += 1;
+        } else if QUADRANT_2.0.contains(&robot.position.0) && QUADRANT_2.1.contains(&robot.position.1) {
+            quadrants.1 += 1;
+        } else if QUADRANT_3.0.contains(&robot.position.0) && QUADRANT_3.1.contains(&robot.position.1) {
+            quadrants.2 += 1;
+        } else if QUADRANT_4.0.contains(&robot.position.0) && QUADRANT_4.1.contains(&robot.position.1) {
+            quadrants.3 += 1;
+        }
+    }
+
+    println!("Result: {}", quadrants.0 * quadrants.1 * quadrants.2 * quadrants.3);
+}

day14/part2.rs

@@ -0,0 +1,57 @@
+const INPUT: &str = include_str!("input.txt");
+const GRID_WIDTH: i64 = 101;
+const GRID_HEIGHT: i64 = 103;
+
+const SQUARE_THRESHOLD: i64 = 4; // 4x4 square
+
+#[derive(Debug)]
+pub struct Robot {
+    pub position: (i64, i64),
+    pub velocity: (i64, i64),
+}
+
+fn main() {
+    let mut robots = INPUT
+        .lines()
+        .map(|l| l.split_once(" v=").unwrap())
+        .map(|(p, v)| {
+            (
+                p.trim_start_matches("p=").split_once(",").unwrap(),
+                v.split_once(",").unwrap(),
+            )
+        })
+        .map(|(p, v)| Robot {
+            position: (p.0.parse().unwrap(), p.1.parse().unwrap()),
+            velocity: (v.0.parse().unwrap(), v.1.parse().unwrap()),
+        })
+        .collect::<Vec<_>>();
+    
+    let mut i = 0u64;
+    loop {
+        i += 1;
+        for robot in robots.iter_mut() {
+            robot.position = (
+                ((robot.position.0 + robot.velocity.0)).rem_euclid(GRID_WIDTH),
+                ((robot.position.1 + robot.velocity.1)).rem_euclid(GRID_HEIGHT),
+            );
+        }
+
+        // Check for square
+        let square = robots.iter().map(|r| r.position).any(
+            |(start_x, start_y)|
+                (start_x..(start_x + SQUARE_THRESHOLD)).all(
+                    |x|
+                        (start_y..(start_y + SQUARE_THRESHOLD)).all(
+                            |y|
+                                robots.iter().any(
+                                    |r|
+                                        r.position == (x, y)
+                                )
+                        )
+                )
+        );
+        if square { break; }
+    }
+
+    println!("Result: {}", i);
+}