From eb767eb50b22293cac7cdf1213f698cb0b698b5f Mon Sep 17 00:00:00 2001 From: "Timothy J. Warren" Date: Tue, 13 Dec 2022 17:11:45 -0500 Subject: [PATCH] Complete day 9 --- day9/src/main.rs | 108 +++++++++++++++++++++++++++------------ day9/src/test-input2.txt | 8 +++ 2 files changed, 83 insertions(+), 33 deletions(-) create mode 100644 day9/src/test-input2.txt diff --git a/day9/src/main.rs b/day9/src/main.rs index 7e9eca2..789c910 100644 --- a/day9/src/main.rs +++ b/day9/src/main.rs @@ -53,25 +53,35 @@ impl Location { #[derive(Debug, Default)] struct Rope { - head: Location, - tail: Location, + knots: Vec, + knot_count: usize, head_visited: HashSet, tail_visited: HashSet, } impl Rope { - pub fn new() -> Self { + pub fn new(knot_count: usize) -> Self { let mut rope = Self::default(); + rope.knot_count = knot_count; rope.head_visited.insert(Location::default()); rope.tail_visited.insert(Location::default()); + rope.knots.resize_with(knot_count, Location::default); rope } + pub fn get_knot(&self, idx: usize) -> Location { + self.knots[idx] + } + + pub fn is_tail(&self, idx: usize) -> bool { + idx == (self.knot_count - 1) + } + pub fn move_head(&mut self, moves: Move) { for _ in 0..moves.amount { - let mut x = self.head.x; - let mut y = self.head.y; + let mut x = self.knots[0].x; + let mut y = self.knots[0].y; match moves.dir { Up => { @@ -89,44 +99,50 @@ impl Rope { } let to = Location::new(x, y); + self.knots[0] = to; - self.move_tail(to); - self.head = to; - self.head_visited.insert(to); + for i in 1..self.knot_count { + self.move_knot(i, i - 1); + } + // self.head = to; + // self.head_visited.insert(to); } } - fn must_tail_move(&mut self, head: Location) -> bool { - let distance = self.tail.get_distance(head); + fn must_move(&mut self, current: usize, prev: usize) -> bool { + let distance = self.get_knot(current).get_distance(self.get_knot(prev)); distance >= 2.0 } - fn move_tail(&mut self, head: Location) { - if !self.must_tail_move(head) { + fn move_knot(&mut self, c: usize, p: usize) { + if !self.must_move(c, p) { return; } - let mut tail = self.tail.clone(); + let mut current = self.get_knot(c); + let prev = self.get_knot(p); - if tail.y != head.y { - if head.y - tail.y < 0 { - tail.y -= 1; + if current.y != prev.y { + if prev.y - current.y < 0 { + current.y -= 1; } else { - tail.y += 1; + current.y += 1; } } - if tail.x != head.x { - if head.x - tail.x < 0 { - tail.x -= 1; + if current.x != prev.x { + if prev.x - current.x < 0 { + current.x -= 1; } else { - tail.x += 1; + current.x += 1; } } - self.tail = tail; - self.tail_visited.insert(tail); + self.knots[c] = current; + if self.is_tail(c) { + self.tail_visited.insert(current); + } } fn get_tail_pos_count(&self) -> usize { @@ -138,7 +154,8 @@ impl Rope { fn main() { let file_str = include_str!("input.txt"); - let mut rope = Rope::new(); + + let mut rope = Rope::new(2); file_str .lines() @@ -147,17 +164,30 @@ fn main() { let tail_positions = rope.get_tail_pos_count(); - println!("Part 1: Number of tail movements: {}", tail_positions); + println!( + "Part 1: Number of tail movements with 2 knots: {}", + tail_positions + ); + + let mut rope = Rope::new(10); + + file_str + .lines() + .map(Move::from_line) + .for_each(|m| rope.move_head(m)); + + let tail_positions = rope.get_tail_pos_count(); + + println!( + "Part 2: Number of tail movements with 10 knots: {}", + tail_positions + ); } #[cfg(test)] mod tests { use super::*; - fn get_data() -> &'static str { - include_str!("test-input.txt") - } - #[test] fn test_location_get_distance() { let a = Location::new(0, 0); @@ -169,15 +199,27 @@ mod tests { #[test] fn test_get_tail_position_count() { - let mut rope = Rope::new(); + let file_str = include_str!("test-input.txt"); + let mut rope = Rope::new(2); - assert_eq!(rope.get_tail_pos_count(), 1); - - get_data() + file_str .lines() .map(Move::from_line) .for_each(|m| rope.move_head(m)); assert_eq!(rope.get_tail_pos_count(), 13); } + + #[test] + fn test_get_tail_position_count_10_knots() { + let file_str = include_str!("test-input2.txt"); + let mut rope = Rope::new(10); + + file_str + .lines() + .map(Move::from_line) + .for_each(|m| rope.move_head(m)); + + assert_eq!(rope.get_tail_pos_count(), 36); + } } diff --git a/day9/src/test-input2.txt b/day9/src/test-input2.txt new file mode 100644 index 0000000..60bd43b --- /dev/null +++ b/day9/src/test-input2.txt @@ -0,0 +1,8 @@ +R 5 +U 8 +L 8 +D 3 +R 17 +D 10 +L 25 +U 20