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Added solution for day 17

main
Sebastian 5 months ago
parent
commit
a2b4066618
  1. 1
      inputs/day17.txt
  2. 2
      inputs/sample.txt
  3. 106
      src/bin/day17.rs

1
inputs/day17.txt

@ -0,0 +1 @@
target area: x=209..238, y=-86..-59

2
inputs/sample.txt

@ -1 +1 @@
8A004A801A8002F478
target area: x=20..30, y=-10..-5

106
src/bin/day17.rs

@ -0,0 +1,106 @@
use std::cmp::Ordering;
use std::collections::BinaryHeap;
use std::collections::HashMap;
use std::collections::HashSet;
use std::error::Error;
use std::fs::File;
use std::io::{self, BufRead};
use std::vec::Vec;
#[macro_use]
extern crate lazy_static;
extern crate regex;
use regex::Regex;
fn is_hit(
mut vx: i64,
mut vy: i64,
target_min_x: i64,
target_max_x: i64,
target_min_y: i64,
target_max_y: i64,
) -> (bool, i64) {
let mut x: i64 = 0;
let mut y: i64 = 0;
let mut max_y = y;
while x < target_max_x && y > target_min_y {
x += vx;
y += vy;
if y > max_y {
max_y = y;
}
if vx != 0 {
vx -= 1;
}
vy -= 1;
if x >= target_min_x && x <= target_max_x && y >= target_min_y && y <= target_max_y {
return (true, max_y);
}
}
(false, 0)
}
fn parse_line(line: &str) -> (i64, i64, i64, i64) {
lazy_static! {
static ref LINE_RE: Regex =
Regex::new(r"^target area: x=([0-9]+)\.\.([0-9]+), y=(-[0-9]+)\.\.(-[0-9]+)$").unwrap();
}
let cap = LINE_RE.captures_iter(&line).nth(0).unwrap();
(
cap[1].parse::<i64>().unwrap(),
cap[2].parse::<i64>().unwrap(),
cap[3].parse::<i64>().unwrap(),
cap[4].parse::<i64>().unwrap(),
)
}
fn main() -> Result<(), Box<dyn Error>> {
let file = File::open("inputs/day17.txt")?;
let line: String = io::BufReader::new(file).lines().next().unwrap()?;
let target = parse_line(&line);
let mut max_y = 0;
let mut max_velocities = (0, 0);
for vx in 0..256 {
for vy in 0..246 {
let (hit, local_max_y) = is_hit(vx, vy, target.0, target.1, target.2, target.3);
if hit {
println!("Hit {} {}: {}", vx, vy, max_y);
if local_max_y > max_y {
max_y = local_max_y;
max_velocities = (vx, vy);
}
}
}
}
println!("Velocities: {},{}", max_velocities.0, max_velocities.1);
println!("Answer1: {}", max_y);
let mut hits = 0;
for vx in -256..256 {
for vy in -256..246 {
let (hit, local_max_y) = is_hit(vx, vy, target.0, target.1, target.2, target.3);
if hit {
println!("Hit {} {}: {}", vx, vy, local_max_y);
hits += 1;
}
}
}
println!("Answer2: {}", hits);
Ok(())
}
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