64 lines
1.7 KiB
Rust
64 lines
1.7 KiB
Rust
use std::collections::HashMap;
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use std::error::Error;
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use std::fs::File;
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use std::io::{self, BufRead};
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use std::vec::Vec;
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fn main() -> Result<(), Box<dyn Error>> {
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let file = File::open("inputs/day14.txt")?;
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let mut lines = io::BufReader::new(file).lines();
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let mut polymer_template: Vec<char> = lines.next().unwrap().unwrap().chars().collect();
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lines.next();
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let mut rules: HashMap<(char, char), char> = HashMap::new();
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while let Some(Ok(line)) = lines.next() {
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if line == "" {
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break;
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}
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let mut parts = line.split(" -> ");
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let pair = parts.next().unwrap();
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let new = parts.next().unwrap();
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rules.insert(
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(pair.chars().nth(0).unwrap(), pair.chars().nth(1).unwrap()),
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new.chars().nth(0).unwrap(),
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);
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}
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for i in 0..40 {
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let mut next_step: Vec<char> = Vec::new();
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next_step.push(polymer_template[0]);
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for pair in polymer_template.windows(2) {
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//next_step.push(pair[0]);
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if rules.contains_key(&(pair[0], pair[1])) {
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next_step.push(rules[&(pair[0], pair[1])]);
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}
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next_step.push(pair[1]);
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}
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polymer_template = next_step;
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println!("{} : {}", i, polymer_template.len());
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}
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let mut dist: HashMap<char, usize> = HashMap::new();
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for c in polymer_template.iter() {
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let count = dist.get(c).unwrap_or_else(|| &0).clone();
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dist.insert(*c, count + 1);
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}
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let mut counts: Vec<&usize> = dist.values().collect();
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counts.sort();
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println!(
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"Answer1: {}",
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*counts.last().unwrap() - *counts.first().unwrap()
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);
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println!("Answer2: {}", 0);
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Ok(())
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}
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