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|
use nom::{
character::complete::{line_ending, u64 as nom_u64},
combinator::map,
multi::separated_list1,
IResult,
};
use std::fs;
fn main() -> Result<(), Box<dyn std::error::Error>> {
let input = fs::read_to_string("inputs/day_1.txt")?;
let sonar_scan = parse_sonar_scan(&input).unwrap().1;
let simple_increase_counter = count_increases(sonar_scan.iter());
dbg!(simple_increase_counter);
let windowed_sonar_scan = sonar_scan
.iter()
.zip(sonar_scan.iter().skip(1))
.zip(sonar_scan.iter().skip(2))
.map(|((depth1, depth2), depth3)| ThreeDepthWindowSum::new([*depth1, *depth2, *depth3]))
.collect::<Vec<_>>();
let windowed_increase_counter = count_increases(windowed_sonar_scan.iter());
dbg!(windowed_increase_counter);
Ok(())
}
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy)]
struct Depth(u64);
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy)]
struct ThreeDepthWindowSum(u64);
impl ThreeDepthWindowSum {
fn new(depths: [Depth; 3]) -> ThreeDepthWindowSum {
ThreeDepthWindowSum(depths.into_iter().map(|d| d.0).sum())
}
}
fn parse_sonar_scan(input: &str) -> IResult<&str, Vec<Depth>> {
separated_list1(line_ending, parse_depth)(input)
}
fn parse_depth(input: &str) -> IResult<&str, Depth> {
map(nom_u64, Depth)(input)
}
#[derive(Default, Debug)]
struct DepthIncreaseCounter(u64);
impl DepthIncreaseCounter {
fn increment(&mut self) {
self.0 += 1;
}
}
fn count_increases<T: Ord>(i: impl IntoIterator<Item = T> + Clone) -> DepthIncreaseCounter {
let mut increases = DepthIncreaseCounter::default();
for (depth, next_depth) in i.clone().into_iter().zip(i.into_iter().skip(1)) {
if next_depth > depth {
increases.increment();
}
}
increases
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn parses_a_depth() {
assert_eq!(parse_depth("96\n"), Ok(("\n", Depth(96))));
}
}
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