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70 lines
1.7 KiB
70 lines
1.7 KiB
use std::error;
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use std::fs::File;
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use std::io::BufRead;
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use std::io::BufReader;
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use regex::Regex;
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fn main() -> Result<(), Box<dyn error::Error>> {
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let f = File::open("input.txt")?;
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let reader = BufReader::new(f);
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let mut lines = reader.lines();
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let mut items: Vec<Vec<&str>> = Vec::new();
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// read the initial state
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let mut init_lines: Vec<String> = vec![];
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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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init_lines.push(line);
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}
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init_lines.reverse();
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let mut count = 0;
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for (i, line) in init_lines.iter().enumerate() {
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// init the items with the right amount of Vecs
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if i == 0 {
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count = line.split_whitespace().count();
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for _ in 0..count {
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items.push(vec![]);
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}
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continue;
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}
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// add the items to the vecs
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// let line_iter = line.chars();
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for i in 0..count {
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let item = &line[(i * 4 + 1)..(i * 4 + 2)];
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if item == " " {
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continue;
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}
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items[i].push(&item);
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}
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}
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// read the movements
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let re = Regex::new(r"^move (\d+) from (\d+) to (\d+)$")?;
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while let Some(Ok(line)) = lines.next() {
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// println!("{:?}", re.captures(&line));
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// println!("{:?}", items);
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let cap: Vec<usize> = re.captures(&line).ok_or("Could not match line")?.iter().skip(1).map(|x| x.unwrap().as_str().parse().unwrap()).collect();
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let mut items_to_move = vec![];
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for _ in 0..cap[0] {
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let item = items[cap[1] - 1].pop().ok_or("Found a broken match")?;
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items_to_move.push(item);
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}
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for item in items_to_move.iter().rev() {
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items[cap[2] - 1].push(item);
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}
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}
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// output the result (top of each item-stack i.e. end of the Vec)
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// println!("{:?}", items);
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println!("{}", items.iter().map(|v| String::from(*v.iter().last().unwrap())).collect::<Vec<_>>().join(""));
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Ok(())
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}
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