Stefan Müller
124 lines
3.8 KiB
Rust
124 lines
3.8 KiB
Rust
use crate::interval::Interval;
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use std::collections::BTreeSet;
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use std::fs::File;
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use std::io;
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use std::io::BufRead;
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use std::path::Path;
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pub struct Cafeteria {
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part1: u64,
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part2: u64,
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}
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impl Cafeteria {
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pub fn new() -> Cafeteria {
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Cafeteria { part1: 0, part2: 0 }
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}
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pub fn run(&mut self) {
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println!("--- Day 5: Cafeteria ---");
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// The "../../data" and "../../../data" paths are useful for running the binary from
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// "target/release/" directory with "data/" directory in package root or parent directory.
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let paths = vec!["./data", "../data", "../../data", "../../../data"];
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match read_data_file("cafeteria.txt", &paths) {
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Ok(lines) => {
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self.process_data(lines);
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self.print_result();
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}
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Err(error) => eprintln!("{}", error),
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};
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}
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fn process_data(&mut self, mut lines: io::Lines<io::BufReader<File>>) {
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// Builds intervals collection.
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let mut intervals: BTreeSet<Interval> = BTreeSet::new();
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for line in lines
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.by_ref()
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.map_while(|x| x.ok().filter(|s| !s.is_empty()))
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{
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let values: Vec<u64> = line.split('-').map_while(|s| s.parse().ok()).collect();
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let mut interval = Interval::new(values[0], values[1]);
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let mut to_delete = Vec::new();
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for next in intervals.range(&interval..) {
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if interval.contains(next.start) || interval.end + 1 == next.start {
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// New interval overlaps with the "next" interval already in the collection.
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if interval.end < next.end {
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interval.end = next.end;
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}
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to_delete.push(next.clone());
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} else {
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break;
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}
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}
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let mut do_insert = true;
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if let Some(prev) = intervals.range(..=&interval).next_back() {
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if interval.contains(prev.end) || prev.end + 1 == interval.start {
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// Enlarges new interval to replace the "previous" interval already in the collection.
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interval.start = prev.start;
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to_delete.push(prev.clone());
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} else if interval.end <= prev.end {
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do_insert = false;
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}
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}
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for del in to_delete {
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intervals.remove(&del);
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}
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if do_insert {
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intervals.insert(interval);
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}
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}
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// Tests values against intervals.
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for value in lines.map_while(|x| x.ok()?.parse::<u64>().ok()) {
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if intervals.iter().any(|interval| interval.contains(value)) {
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self.part1 += 1;
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}
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}
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self.part2 = intervals.iter().map(|x| x.len()).sum();
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}
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fn print_result(&self) {
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println!("Part 1: {:?}\nPart 2: {:?}\n", self.part1, self.part2);
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}
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}
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fn read_data_file<T>(
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filename: T,
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search_paths: &Vec<T>,
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) -> Result<io::Lines<io::BufReader<File>>, String>
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where
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T: AsRef<Path>,
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{
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for path in search_paths {
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if let Ok(lines) = read_lines(path.as_ref().join(&filename)) {
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return Ok(lines);
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}
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}
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let message = search_paths
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.iter()
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.map(|path| path.as_ref().join(&filename).display().to_string())
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.collect::<Vec<_>>()
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.join("\n");
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Err(format!(
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"Cannot open puzzle input file, searched these paths:\n{}",
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message
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))
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}
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// This code is taken from https://doc.rust-lang.org/stable/rust-by-example/std_misc/file/read_lines.html
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fn read_lines<T>(filename: T) -> io::Result<io::Lines<io::BufReader<File>>>
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where
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T: AsRef<Path>,
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{
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let file = File::open(filename)?;
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Ok(io::BufReader::new(file).lines())
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}
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