83 lines
1.9 KiB
Rust
83 lines
1.9 KiB
Rust
#![feature(test)]
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use regex::Regex;
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use rustc_hash::{FxHashMap, FxHashSet};
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struct Input {
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x1: i32,
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x2: i32,
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y1: i32,
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y2: i32,
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}
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fn setup(input: &str) -> Input {
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let regex = Regex::new(r"^target area: x=(-?\d+)..(-?\d+), y=(-?\d+)..(-?\d+)$").unwrap();
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let capture = regex.captures(input.trim()).unwrap();
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let get = |i| capture.get(i).unwrap().as_str().parse().unwrap();
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Input {
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x1: get(1),
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x2: get(2),
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y1: get(3),
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y2: get(4),
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}
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}
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fn solve(input: &Input) -> (i32, usize) {
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let mut maxt = 0;
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let mut ok = FxHashMap::default();
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for ovy in input.y1..500 {
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let mut vy = ovy;
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let mut t = 0;
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let mut y = 0;
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let mut maxy = 0;
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while y >= input.y1 {
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if y <= input.y2 {
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ok.entry(t).or_insert_with(|| (0, FxHashSet::default()));
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let (my, vys) = ok.get_mut(&t).unwrap();
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*my = maxy.max(*my);
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vys.insert(ovy);
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maxt = maxt.max(t);
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}
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y += vy;
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maxy = maxy.max(y);
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vy -= 1;
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t += 1;
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}
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}
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let mut outa = 0;
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let mut outb = 0;
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for mut vx in 1..=input.x2 {
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let mut t = 0;
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let mut x = 0;
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let mut found = FxHashSet::default();
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while x <= input.x2 && t <= maxt {
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if input.x1 <= x {
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if let Some((a, b)) = ok.get(&t) {
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outa = outa.max(*a);
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for k in b {
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found.insert(*k);
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}
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}
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}
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x += vx;
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vx = 0.max(vx - 1);
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t += 1;
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}
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outb += found.len();
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}
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(outa, outb)
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}
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fn part1(input: &Input) -> i32 {
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solve(input).0
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}
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fn part2(input: &Input) -> usize {
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solve(input).1
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}
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aoc::main!(2021, 17, ex: 1);
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