161 lines
4.0 KiB
Rust
161 lines
4.0 KiB
Rust
use crate::Day;
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use anyhow::Result;
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pub struct Day03(Vec<Vec<bool>>);
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impl Day for Day03 {
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fn init(content: String) -> Result<Self> {
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let v = content.lines().map(split_lines).collect();
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Ok(Self(v))
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}
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fn part1(&self) -> Result<String> {
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Ok(format!("{}", self.gamma() * self.epsilon()))
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}
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fn part2(&self) -> Result<String> {
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Ok(format!("{}", self.ox() * self.co2()))
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}
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}
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impl Day03 {
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pub fn gamma_calc(&self) -> Vec<bool> {
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let mut result = Vec::new();
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for i in 0..self.0[0].len() {
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let bit = !matches!(most_common_bit(&self.0.clone(), i), CommonBit::Zero);
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result.push(bit);
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}
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result
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}
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pub fn eps_calc(&self) -> Vec<bool> {
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let mut result = Vec::new();
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for i in 0..self.0[0].len() {
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let bit = !matches!(most_common_bit(&self.0.clone(), i), CommonBit::Zero);
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result.push(!bit);
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}
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result
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}
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pub fn get_oxygen_generator_rating_binary(&self) -> Vec<bool> {
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let mut working_set = self.0.clone();
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for i in 0..self.0[0].len() {
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let common_bit = !matches!(most_common_bit(&working_set.clone(), i), CommonBit::Zero);
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working_set = working_set
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.into_iter()
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.filter(|x| x[i] == common_bit)
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.collect();
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if working_set.len() == 1 {
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break;
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}
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}
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working_set[0].clone()
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}
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pub fn get_co2_scrubber_rating_binary(&self) -> Vec<bool> {
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let mut working_set = self.0.clone();
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for i in 0..self.0[0].len() {
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let common_bit = matches!(least_common_bit(&working_set.clone(), i), CommonBit::One);
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working_set = working_set
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.into_iter()
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.filter(|x| x[i] == common_bit)
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.collect();
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if working_set.len() == 1 {
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break;
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}
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}
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working_set[0].clone()
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}
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pub fn gamma(&self) -> u32 {
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convert(&self.gamma_calc())
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}
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pub fn epsilon(&self) -> u32 {
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convert(&self.eps_calc())
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}
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pub fn ox(&self) -> u32 {
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convert(&self.get_oxygen_generator_rating_binary())
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}
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pub fn co2(&self) -> u32 {
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convert(&self.get_co2_scrubber_rating_binary())
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}
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}
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enum CommonBit {
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Zero,
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One,
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Equal,
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}
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fn most_common_bit(set: &[Vec<bool>], bit_position: usize) -> CommonBit {
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let ones_count = set.iter().fold(
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0,
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|ones, code| if code[bit_position] { ones + 1 } else { ones },
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);
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let len = (set.len() + 1) / 2;
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match ones_count.cmp(&len) {
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std::cmp::Ordering::Less => CommonBit::Zero,
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std::cmp::Ordering::Equal => CommonBit::Equal,
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std::cmp::Ordering::Greater => CommonBit::One,
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}
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}
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fn least_common_bit(set: &[Vec<bool>], bit_position: usize) -> CommonBit {
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let ones_count = set.iter().fold(
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0,
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|ones, code| if code[bit_position] { ones + 1 } else { ones },
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);
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let len = (set.len() + 1) / 2;
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match ones_count.cmp(&len) {
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std::cmp::Ordering::Less => CommonBit::One,
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std::cmp::Ordering::Equal => CommonBit::Equal,
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std::cmp::Ordering::Greater => CommonBit::Zero,
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}
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}
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pub fn convert(binary: &[bool]) -> u32 {
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binary.iter().fold(0, |result, &bit| (result << 1) ^ bit as u32)
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}
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fn split_lines(content: &str) -> Vec<bool> {
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content.chars().map(|x| x == '1').collect()
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}
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#[cfg(test)]
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mod tests {
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use crate::{Day03, day_tests};
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use crate::day::Day;
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use anyhow::Result;
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const INPUT: &str = r"00100
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11110
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10110
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10111
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10101
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01111
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00111
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11100
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10000
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11001
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00010
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01010";
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#[test]
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fn part1_test() -> Result<()>{
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let t = Day03::init(String::from(INPUT))?;
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let p1 = t.part1()?;
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assert_eq!("198", p1);
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Ok(())
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}
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#[test]
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fn part2_test() -> Result<()>{
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let t = Day03::init(String::from(INPUT))?;
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let p2 = t.part2()?;
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assert_eq!("230", p2);
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Ok(())
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}
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day_tests!(Day03, "03", "4118544", "3832770");
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} |