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authorMartin Ashby <martin@ashbysoft.com>2022-12-18 23:30:44 +0000
committerMartin Ashby <martin@ashbysoft.com>2022-12-18 23:31:38 +0000
commitabbb602726f39356b3b525b7e0f2f4f06c3e9489 (patch)
tree714a8f7f683b008ff63db967c4a810aa05652dfa /src
parentb29e650c66a3efe3cffe56ba0c41338072eac09f (diff)
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day17
Found an approach I think will work
Diffstat (limited to 'src')
-rw-r--r--src/day17.rs63
-rw-r--r--src/main.rs3
2 files changed, 52 insertions, 14 deletions
diff --git a/src/day17.rs b/src/day17.rs
index d8953ee..e965af6 100644
--- a/src/day17.rs
+++ b/src/day17.rs
@@ -1,6 +1,6 @@
//use std::{thread::{sleep}, time::Duration};
-use std::{collections::VecDeque, thread::sleep, time::Duration};
+use std::{collections::{VecDeque, HashSet, HashMap}, thread::sleep, time::Duration};
const ROCK: char = '#';
const AIR: char = '.';
@@ -42,7 +42,7 @@ impl Grid {
// cheat, jjust keep the top 100 rows
// really we should check for impassable points
// I don't really like this solution either tbh, I want an rtruncate method...
- let tt = self.rows.len() as i32 - 30;
+ let tt = self.rows.len() as i64 - 200;
if tt > 0 {
for _ in 0..tt {
let _ = self.rows.pop_front();
@@ -66,7 +66,7 @@ impl Grid {
for (y ,row) in self.rows.iter().rev() {
print!("{:012} ", y);
for (x, cell) in row.iter().enumerate() {
- if pts.contains(&Pos{x:(x as i32),y:(*y as i32)}) {
+ if pts.contains(&Pos{x:(x as i64),y:(*y as i64)}) {
print!("@");
} else {
print!("{}", cell);
@@ -76,17 +76,22 @@ impl Grid {
}
println!("+++++++ height: {} rocks: {}", self.rock_height(), rock_count);
}
+ fn height_adjust(&mut self, x: usize) {
+ for mut row in self.rows.iter_mut() {
+ row.0 += x;
+ }
+ }
}
#[derive(Debug,Clone,PartialEq)]
struct Pos {
- x: i32,
- y: i32,
+ x: i64,
+ y: i64,
}
impl Pos {
- fn new(x:i32,y:i32) -> Pos {
+ fn new(x:i64,y:i64) -> Pos {
Pos{x, y}
}
fn translate(&self, other: &Pos) -> Pos {
@@ -163,7 +168,7 @@ impl Rock {
// Bounds check
p.y < 0 ||
p.x < 0 ||
- p.x >= Grid::WIDTH as i32 ||
+ p.x >= Grid::WIDTH as i64 ||
// Intersecting another rock?
grid.get(p) != AIR
}) {
@@ -182,17 +187,24 @@ impl Rock {
}
pub fn run(input: String) {
- let mut rocks = vec![RockType::Bar,RockType::Cross,RockType::Ell,RockType::VBar,RockType::Square].into_iter().cycle();
- let mut gas_jets = input.chars().cycle();
+ let mut rocks = vec![RockType::Bar,RockType::Cross,RockType::Ell,RockType::VBar,RockType::Square].into_iter().enumerate().cycle();
+ let mut gas_jets = input.chars().enumerate().cycle();
+
+
let mut grid: Grid = Grid::new();
+ let (mut rtypeix, mut rtype) = rocks.next().unwrap();
let mut rock = Rock{
- rtype: rocks.next().unwrap(),
+ rtype: rtype,
pos: Pos{x: 2, y: 3}
};
+
let mut rock_count: usize = 1;
+
+ let mut track: HashMap<(usize,usize),(usize,usize)> = HashMap::new();
'lp: loop {
- let push = match gas_jets.next().unwrap() {
+ let (gasjetix, gas_jet) = gas_jets.next().unwrap();
+ let push = match gas_jet {
'>' => Direction::Right,
'<' => Direction::Left,
dir => panic!("Unexpected jet direction! {}", dir)
@@ -216,9 +228,10 @@ pub fn run(input: String) {
println!("Done {} rocks...", rock_count);
}
// Spawn new rock
+ (rtypeix,rtype) = rocks.next().unwrap();
Rock {
- rtype: rocks.next().unwrap(),
- pos: Pos{x: 2, y: max_rock as i32 +3 }
+ rtype: rtype,
+ pos: Pos{x: 2, y: max_rock as i64 +3 }
}
}
};
@@ -229,6 +242,30 @@ pub fn run(input: String) {
// sleep(Duration::from_millis(50));
// It just isn't enough.. we need to detect the repeating pattern!!!!! or find a fast enough computer :D
+ let track_key = (gasjetix,rtypeix);
+ if let Some((prev_rock_count, prev_rock_height)) = track.get(&track_key) {
+
+ let rcp = rock_count - *prev_rock_count;
+ let rhp = grid.rock_height() - *prev_rock_height;
+ let rco= *prev_rock_count;
+ let rho = *prev_rock_height;
+ // find max n such that
+ // (n * rcp) + rco <= 1_000_000_000_000;
+ let n:usize = (1_000_000_000_000 - rco) / rcp;
+ // set rock_count to P
+ // (n * rcp) + rco = P;
+ rock_count = n * rcp + rco;
+ // set rock_height to X
+ // (n * rhp) + rho = X;
+ let new_rock_height = (n * rhp) + rho;
+ let rhd = new_rock_height - grid.rock_height();
+ grid.height_adjust(rhd);
+ rock.pos.y += rhd as i64;
+ println!("Periodicity encountered, zipping ahead rcp {} rhp {} rco {} rho {} n {} rock_count {} new_rock_height {} rhd {}", rcp, rhp, rco, rho, n, rock_count, new_rock_height, rhd);
+ grid.print(&rock, rock_count);
+ } else {
+ track.insert(track_key, (rock_count, grid.rock_height()));
+ }
}
println!("Day 17: {}", grid.rock_height());
} \ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
index 34d8bad..47f41a7 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,6 @@
#![feature(get_many_mut)]
#![feature(iterator_try_collect)]
+#![feature(int_roundings)]
use std::fs;
// mod day1;
@@ -37,5 +38,5 @@ fn main() {
// day14::run(fs::read_to_string("input/day14.txt").expect("Failed to read input file!"));
// day15::run(fs::read_to_string("input/day15.txt").expect("Failed to read input file!"));
// day16::run(fs::read_to_string("input/day16.txt").expect("Failed to read input file!"));
- day17::run(fs::read_to_string("input/day17_ex.txt").expect("Failed to read input file!"));
+ day17::run(fs::read_to_string("input/day17.txt").expect("Failed to read input file!"));
}