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Day 8: minimizing assumptions about decode_digit inputs

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Zoé Cassiopée Gauthier 2021-12-08 17:10:39 -05:00
parent 122e818060
commit 53cb025cfc
1 changed files with 11 additions and 9 deletions
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20
src/day8.rs
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@ -23,9 +23,11 @@ fn hash(s: &str) -> u32 {
.product() .product()
} }
fn decode_digit(patterns: &[&str], digit_positions: &[u32], output: &str) -> u32 { fn decode_digit<'a, I>(patterns: &[&str], digit_positions: I, output: &str) -> u32
where
I: Iterator<Item = &'a u32>,
{
*digit_positions *digit_positions
.iter()
.zip(patterns) .zip(patterns)
.find(|(_i, p)| hash(p) == hash(output)) .find(|(_i, p)| hash(p) == hash(output))
.unwrap() .unwrap()
@ -37,7 +39,7 @@ fn decode(patterns: Vec<&str>, outputs: Vec<&str>) -> u32 {
let four = patterns.iter().find(|p| p.len() == 4).unwrap(); let four = patterns.iter().find(|p| p.len() == 4).unwrap();
let bd = find_bd(one, four); let bd = find_bd(one, four);
let digit_positions: Vec<u32> = patterns let digit_positions = patterns
.iter() .iter()
.map(|p| match p.len() { .map(|p| match p.len() {
2 => 1, 2 => 1,
@ -52,18 +54,18 @@ fn decode(patterns: Vec<&str>, outputs: Vec<&str>) -> u32 {
6 if contains(p, one) && !contains(p, four) => 0, 6 if contains(p, one) && !contains(p, four) => 0,
_ => panic!(), _ => panic!(),
}) })
.collect(); .collect::<Vec<u32>>();
let mut iter = outputs.iter(); let mut iter = outputs.iter();
decode_digit(&patterns, &digit_positions, iter.next().unwrap()) * 1000 decode_digit(&patterns, digit_positions.iter(), iter.next().unwrap()) * 1000
+ decode_digit(&patterns, &digit_positions, iter.next().unwrap()) * 100 + decode_digit(&patterns, digit_positions.iter(), iter.next().unwrap()) * 100
+ decode_digit(&patterns, &digit_positions, iter.next().unwrap()) * 10 + decode_digit(&patterns, digit_positions.iter(), iter.next().unwrap()) * 10
+ decode_digit(&patterns, &digit_positions, iter.next().unwrap()) + decode_digit(&patterns, digit_positions.iter(), iter.next().unwrap())
} }
fn main() { fn main() {
const INPUT: &str = include_str!("../inputs/day8.txt"); const INPUT: &str = include_str!("../inputs/day8.txt");
let easy_digits: usize = INPUT let easy_digits = INPUT
.lines() .lines()
.map(|line| { .map(|line| {
line.split_ascii_whitespace() line.split_ascii_whitespace()