109 lines
2.7 KiB
Rust
109 lines
2.7 KiB
Rust
use std::collections::HashMap;
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use std::fs::File;
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use std::io::{BufRead, BufReader, Lines};
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use std::time::{Duration, Instant};
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use itertools::Itertools;
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// BOILERPLATE
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type InputIter = Lines<BufReader<File>>;
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pub fn get_input() -> InputIter {
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let f = File::open("input").unwrap();
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let br = BufReader::new(f);
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br.lines()
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}
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fn duration_format(duration: Duration) -> String {
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match duration.as_secs_f64() {
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x if x > 1.0 => format!("{:.3}s", x),
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x if x > 0.010 => format!("{:.3}ms", x * 1e3),
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x => format!("{:.3}us", x * 1e6),
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}
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}
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fn main() {
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let input = get_input();
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let start = Instant::now();
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let ans1 = problem1(input);
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let duration1 = start.elapsed();
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println!("Problem 1 solution: {} [{}]", ans1, duration_format(duration1));
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let input = get_input();
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let start = Instant::now();
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let ans2 = problem2(input);
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let duration2 = start.elapsed();
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println!("Problem 2 solution: {} [{}]", ans2, duration_format(duration2));
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println!("Total duration: {}", duration_format(duration1 + duration2));
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}
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#[derive(Clone, Copy, Debug, Hash)]
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struct Stone {
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value: u64,
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}
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impl Stone {
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fn blink_once(self) -> Vec<Stone> {
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let n_digits = if self.value == 0 { 1 } else { self.value.ilog10() + 1 };
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if self.value == 0 {
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vec![Stone { value: 1 }]
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} else if n_digits % 2 == 0 {
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let parts = (
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self.value / 10u64.pow(n_digits / 2),
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self.value % 10u64.pow(n_digits / 2),
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);
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vec![Stone { value: parts.0 }, Stone { value: parts.1 }]
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} else {
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vec![Stone {
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value: self.value * 2024,
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}]
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}
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}
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fn blink(self, times: usize) -> Vec<Stone> {
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let mut stones = vec![self];
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for _ in 0..times {
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stones = stones.iter().flat_map(|stone| stone.blink_once()).collect();
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}
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stones
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}
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}
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// PROBLEM 1 solution
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fn problem1<T: BufRead>(mut input: Lines<T>) -> u64 {
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let stones = input
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.next()
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.unwrap()
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.unwrap()
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.split_ascii_whitespace()
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.map(|v| Stone {
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value: v.parse().unwrap(),
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})
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.collect_vec();
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stones.iter().flat_map(|stone| stone.blink(25)).count() as u64
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}
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// PROBLEM 2 solution
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fn problem2<T: BufRead>(mut input: Lines<T>) -> u64 {
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0
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}
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#[cfg(test)]
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mod tests {
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use crate::*;
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use std::io::Cursor;
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const EXAMPLE: &str = &"125 17";
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#[test]
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fn problem1_example() {
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let c = Cursor::new(EXAMPLE);
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assert_eq!(problem1(c.lines()), 55312);
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}
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#[test]
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fn problem2_example() {
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let c = Cursor::new(EXAMPLE);
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assert_eq!(problem2(c.lines()), 0);
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}
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}
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