Day 2: Red-Nosed Reports
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3 points
Rust
use crate::utils::read_lines;
pub fn solution1() {
let reports = get_reports();
let safe_reports = reports
.filter(|report| report.windows(3).all(window_is_valid))
.count();
println!("Number of safe reports = {safe_reports}");
}
pub fn solution2() {
let reports = get_reports();
let safe_reports = reports
.filter(|report| {
(0..report.len()).any(|i| {
[&report[0..i], &report[i + 1..]]
.concat()
.windows(3)
.all(window_is_valid)
})
})
.count();
println!("Number of safe reports = {safe_reports}");
}
fn window_is_valid(window: &[usize]) -> bool {
matches!(window[0].abs_diff(window[1]), 1..=3)
&& matches!(window[1].abs_diff(window[2]), 1..=3)
&& ((window[0] > window[1] && window[1] > window[2])
|| (window[0] < window[1] && window[1] < window[2]))
}
fn get_reports() -> impl Iterator<Item = Vec<usize>> {
read_lines("src/day2/input.txt").map(|line| {
line.split_ascii_whitespace()
.map(|level| {
level
.parse()
.expect("Reactor level is always valid integer")
})
.collect()
})
}
Definitely trickier than yesterday’s. I feel like the windows solution isn’t the best, but it was what came to mind and ended up working for me.