129 lines
3.1 KiB
Rust
129 lines
3.1 KiB
Rust
use crate::common::file::split_lines;
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use super::template::{DayTrait, ResultType};
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use itertools::Itertools;
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use thiserror::Error;
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const DAY_NUMBER: usize = 3;
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pub struct Day;
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impl DayTrait for Day {
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fn get_day_number(&self) -> usize {
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DAY_NUMBER
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}
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fn part1(&self, lines: &str) -> anyhow::Result<ResultType> {
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let sum = split_lines(lines)
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.map(|line| find_double(line))
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.map_ok(priority)
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.flatten_ok()
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.fold_ok(0, |a, b| a + b)?;
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Ok(ResultType::Integer(sum))
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}
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fn part2(&self, lines: &str) -> anyhow::Result<ResultType> {
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let sum = split_lines(lines)
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.chunks(3)
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.into_iter()
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.map(|chunk| find_badge(&chunk.collect_vec()))
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.map_ok(priority)
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.flatten_ok()
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.fold_ok(0, |a, b| a + b)?;
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Ok(ResultType::Integer(sum))
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}
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}
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#[derive(Debug, Error)]
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enum RucksackError {
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#[error("No double item found")]
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NoDoubleFound,
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#[error("Not a valid char: {0}")]
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InvalidChar(char),
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#[error("Need at least two elves for common item")]
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NeedAtLeastTwo,
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#[error("No common badge was found")]
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NoBadgeFound,
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}
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fn priority(c: char) -> Result<i64, RucksackError> {
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match c {
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'a'..='z' => Ok(c as i64 - 'a' as i64 + 1),
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'A'..='Z' => Ok(c as i64 - 'A' as i64 + 27),
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_ => Err(RucksackError::InvalidChar(c)),
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}
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}
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fn find_double(content: &str) -> Result<char, RucksackError> {
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let length = content.len() / 2;
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let part1 = &content[..length];
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let part2 = &content[length..];
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for c in part1.chars() {
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if part2.contains(c) {
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return Ok(c);
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}
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}
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Err(RucksackError::NoDoubleFound)?
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}
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fn find_badge(elves: &[&str]) -> Result<char, RucksackError> {
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if elves.len() < 2 {
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return Err(RucksackError::NeedAtLeastTwo);
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};
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for c in elves[0].chars() {
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let mut found = true;
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for other in &elves[1..] {
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if !other.contains(c) {
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found = false;
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}
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}
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if found {
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return Ok(c);
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}
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}
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Err(RucksackError::NoBadgeFound)
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}
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#[cfg(test)]
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mod test {
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use super::*;
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use crate::common::file::read_string;
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use anyhow::Result;
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#[test]
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fn test_rucksack() -> Result<(), RucksackError> {
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let input = "vJrwpWtwJgWrhcsFMMfFFhFp";
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let expected = 16;
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let result = find_double(input).and_then(priority)?;
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assert_eq!(result, expected);
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Ok(())
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}
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#[test]
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fn test_part1() -> Result<()> {
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let day = Day {};
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let lines = read_string(day.get_day_number(), "example01.txt")?;
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let expected = ResultType::Integer(157);
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let result = day.part1(&lines)?;
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assert_eq!(result, expected);
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Ok(())
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}
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#[test]
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fn test_part2() -> Result<()> {
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let day = Day {};
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let lines = read_string(day.get_day_number(), "example01.txt")?;
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let expected = ResultType::Integer(70);
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let result = day.part2(&lines)?;
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assert_eq!(result, expected);
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Ok(())
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}
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}
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