79 lines
2.3 KiB
Rust
79 lines
2.3 KiB
Rust
#![feature(test)]
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extern crate test;
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use aoc2020::common::*;
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use itertools::Itertools;
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use std::ops::RangeInclusive;
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use text_io::scan;
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#[derive(Debug)]
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struct PasswordVerification {
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required_char: char,
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// Had I known what part 2 was beforehand, I wouldn’t have used a range here. Oh well.
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required_quantity: RangeInclusive<usize>,
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password: String,
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}
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impl From<&'_ str> for PasswordVerification {
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fn from(s: &'_ str) -> Self {
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let required_char: char;
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let lower: usize;
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let upper: usize;
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let password: String;
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scan!(s.bytes() => "{}-{} {}: {}\n", lower, upper, required_char, password);
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PasswordVerification {
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required_char,
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required_quantity: lower..=upper,
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password,
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}
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}
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}
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impl PasswordVerification {
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fn is_valid(&self) -> bool {
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self.required_quantity
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.contains(&self.password.chars().filter(|&c| c == self.required_char).count())
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}
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fn is_valid_part2(&self) -> bool {
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let pw = self.password.as_bytes();
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let (first, second) = (*self.required_quantity.start(), *self.required_quantity.end());
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// 1-based indexing :reeeeeee:
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(pw[first - 1] == self.required_char as u8) ^ (pw[second - 1] == self.required_char as u8)
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}
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}
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fn read_input() -> Vec<PasswordVerification> {
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read_file(2).lines().map_into().collect()
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}
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fn main() {
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let input = read_input();
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let p1 = input.iter().filter(|pw| pw.is_valid()).count();
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println!("{}", p1);
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let p2 = input.iter().filter(|pw| pw.is_valid_part2()).count();
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println!("{}", p2);
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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const TEST_INPUT: &str = "1-3 a: abcde
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1-3 b: cdefg
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2-9 c: ccccccccc";
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#[test]
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fn test_part1() {
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let pws: Vec<PasswordVerification> = TEST_INPUT.lines().map_into().collect_vec();
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let pws = pws.into_iter().filter(|pw| !pw.is_valid()).map(|pw| pw.password).collect_vec();
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assert_eq!(pws, vec![String::from("cdefg")]);
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}
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#[test]
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fn test_part2() {
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let pws: Vec<PasswordVerification> = TEST_INPUT.lines().map_into().collect_vec();
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let pws = pws.into_iter().filter(|pw| pw.is_valid_part2()).map(|pw| pw.password).collect_vec();
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assert_eq!(pws, vec![String::from("abcde")]);
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}
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}
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