144 lines
3.9 KiB
Rust
144 lines
3.9 KiB
Rust
use std::collections::HashSet;
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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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struct Line {
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known_digits: Vec<HashSet<char>>,
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unknown_digits: Vec<HashSet<char>>,
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}
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fn parse_input(line: String) -> Line {
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let mut parts = line.split("|").map(|p| p.trim());
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let known: Vec<HashSet<char>> = parts
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.next()
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.unwrap()
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.split(" ")
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.map(|d| HashSet::from_iter(d.chars()))
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.collect();
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let unknown: Vec<HashSet<char>> = parts
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.next()
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.unwrap()
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.split(" ")
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.map(|d| HashSet::from_iter(d.chars()))
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.collect();
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Line {
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known_digits: known,
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unknown_digits: unknown,
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}
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}
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fn main() -> Result<(), Box<dyn Error>> {
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let file = File::open("inputs/day8.txt")?;
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let lines: Vec<Line> = io::BufReader::new(file)
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.lines()
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.map(|l| parse_input(l.unwrap()))
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.collect();
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let mut count1 = 0;
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let mut answer2 = 0;
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for line in lines.iter() {
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let one = line.known_digits.iter().find(|d| d.len() == 2).unwrap();
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println!("Identified one: {:?}", one);
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let seven = line.known_digits.iter().find(|d| d.len() == 3).unwrap();
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println!("Identified seven: {:?}", seven);
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let four = line.known_digits.iter().find(|d| d.len() == 4).unwrap();
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println!("Identified four: {:?}", four);
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let eight = line.known_digits.iter().find(|d| d.len() == 7).unwrap();
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println!("Identified eight: {:?}", eight);
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for unknown in line.unknown_digits.iter() {
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if unknown == one || unknown == seven || unknown == four || unknown == eight {
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count1 += 1;
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}
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}
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// Part 2
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let nine = line
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.known_digits
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.iter()
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.find(|d| d.len() == 6 && d.is_superset(seven) && d.is_superset(four))
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.unwrap();
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println!("Identified nine: {:?}", nine);
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let three = line
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.known_digits
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.iter()
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.find(|d| d.len() == 5 && d.is_superset(one))
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.unwrap();
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println!("Identified three: {:?}", three);
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let zero = line
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.known_digits
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.iter()
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.find(|d| {
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d.len() == 6 && d.is_superset(one) && d.is_superset(seven) && !d.is_superset(three)
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})
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.unwrap();
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println!("Identified zero: {:?}", zero);
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let six = line
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.known_digits
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.iter()
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.find(|d| d.len() == 6 && d != &zero && d != &nine)
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.unwrap();
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println!("Identified six: {:?}", six);
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let five = line
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.known_digits
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.iter()
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.find(|d| d.len() == 5 && d.is_subset(nine) && d != &three)
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.unwrap();
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println!("Identified five: {:?}", five);
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let two = line
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.known_digits
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.iter()
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.find(|d| d.len() == 5 && d != &three && d != &five)
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.unwrap();
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println!("Identified two: {:?}", two);
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let mut base = 1;
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let mut reading = 0;
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for digit in line.unknown_digits.iter().rev() {
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let d = if digit == zero {
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0
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} else if digit == one {
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1
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} else if digit == two {
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2
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} else if digit == three {
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3
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} else if digit == four {
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4
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} else if digit == five {
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5
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} else if digit == six {
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6
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} else if digit == seven {
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7
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} else if digit == eight {
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8
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} else {
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9
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};
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reading += d * base;
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base *= 10;
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}
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println!("Reading: {}", reading);
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answer2 += reading;
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}
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println!("Answer1: {}", count1);
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println!("Answer2: {}", answer2);
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Ok(())
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}
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