58 lines
1.2 KiB
Rust
58 lines
1.2 KiB
Rust
use aoc_runner_derive::{aoc, aoc_generator};
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pub struct Forest {
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slice: Vec<Vec<bool>>,
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}
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impl Forest {
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fn get(&self, x: usize, y: usize) -> Option<bool> {
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self.slice
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.get(y)
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.map(|line| line.get(x % line.len()))
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.flatten()
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.cloned()
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}
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}
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#[aoc_generator(day3)]
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pub fn input_generator(input: &str) -> Forest {
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let slice = input
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.lines()
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.map(|l| l.chars().map(|c| c == '#').collect())
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.collect();
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Forest { slice }
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}
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#[aoc(day3, part1)]
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pub fn solve_part1(input: &Forest) -> usize {
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let mut sum: usize = 0;
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let dx = 3;
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let dy = 1;
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let mut pos = (0, 0);
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while let Some(tree) = input.get(pos.0, pos.1) {
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if tree {
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sum += 1;
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}
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pos.0 += dx;
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pos.1 += dy;
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}
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sum
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}
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#[aoc(day3, part2)]
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pub fn solve_part2(input: &Forest) -> usize {
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let mut prod: usize = 1;
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for (dx, dy) in &[(1, 1), (3, 1), (5, 1), (7, 1), (1, 2)] {
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let mut sum: usize = 0;
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let mut pos = (0, 0);
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while let Some(tree) = input.get(pos.0, pos.1) {
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if tree {
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sum += 1;
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}
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pos.0 += dx;
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pos.1 += dy;
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}
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prod *= sum;
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}
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prod
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}
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