86 lines
2.5 KiB
Rust
86 lines
2.5 KiB
Rust
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#![allow(dead_code)]
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use std::collections::VecDeque;
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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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use std::time::Instant;
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fn main() {
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let now = Instant::now();
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part_one();
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let part_one_duration = now.elapsed();
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part_two();
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let part_two_duration = now.elapsed();
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println!(
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"p1: {}ms, p2: {}ms",
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part_one_duration.as_millis(),
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(part_two_duration - part_one_duration).as_millis()
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);
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}
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fn read_lines<P>(filename: P) -> io::Result<io::Lines<io::BufReader<File>>>
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where
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P: AsRef<Path>,
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{
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// note that this discards a final newline
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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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fn part_one() {
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if let Ok(mut lines) = read_lines("./inputs/input") {
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if let Some(Ok(signal)) = lines.next() {
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let mut buf = VecDeque::<char>::new();
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for (i, c) in signal.chars().enumerate() {
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if buf.len() < 3 {
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// start of stream
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buf.push_back(c);
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continue;
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} else if buf.contains(&c)
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|| buf[0] == buf[1]
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|| buf[1] == buf[2]
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|| buf[2] == buf[0]
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{
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// repeated character
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buf.pop_front();
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buf.push_back(c);
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} else {
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// found it; offset to the next character
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println!("{}", i + 1);
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return;
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}
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}
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}
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}
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}
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fn part_two() {
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if let Ok(mut lines) = read_lines("./inputs/input") {
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if let Some(Ok(signal)) = lines.next() {
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let mut buf = VecDeque::<char>::new();
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for (i, c) in signal.chars().enumerate() {
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if buf.len() < 13 {
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// start of stream
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buf.push_back(c);
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continue;
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} else if buf.contains(&c)
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|| (1..buf.len()).any(|i| {
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buf.range(i..)
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.collect::<VecDeque<&char>>()
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.contains(&&buf[i - 1]) // neat trick
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})
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{
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// repeated character
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buf.pop_front();
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buf.push_back(c);
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} else {
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// found it; offset to the next character
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println!("{}", i + 1);
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return;
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}
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}
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}
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}
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}
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