56 lines
2.0 KiB
Rust
56 lines
2.0 KiB
Rust
use std::collections::HashSet;
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use std::error::Error;
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use std::str::FromStr;
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use utils::GenericError;
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#[path = "../utils/mod.rs"]
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mod utils;
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fn main() -> Result<(), Box<dyn Error>> {
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let lines = utils::parse_input_lines::<PasswordRule>()?;
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println!("Valid passwords according to part 1 rules: {}", lines.iter().filter(|x| x.is_valid_part1()).count());
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println!("Valid passwords according to part 2 rules: {}", lines.iter().filter(|x| x.is_valid_part2()).count());
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Ok(())
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}
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struct PasswordRule {
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left_value: usize,
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right_value: usize,
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required_char: String,
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actual_password: String
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}
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impl PasswordRule {
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fn is_valid_part1(&self) -> bool {
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let count = self.actual_password.matches(self.required_char.as_str()).count();
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return count >= self.left_value && count <= self.right_value;
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}
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fn is_valid_part2(&self) -> bool {
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let positions = self.actual_password.match_indices(self.required_char.as_str()).map(|(index, _)| index + 1).collect::<HashSet<usize>>();
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let is_in_first_position = positions.contains(&self.left_value);
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let is_in_second_position = positions.contains(&self.right_value);
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return (is_in_first_position && !is_in_second_position) || (!is_in_first_position && is_in_second_position);
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}
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}
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impl FromStr for PasswordRule {
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type Err = GenericError;
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fn from_str(s: &str) -> Result<Self, Self::Err> {
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let (s_range, s_rest) = s.split_once(' ').ok_or(GenericError::new("Missing space."))?;
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let (s_min, s_max) = s_range.split_once('-').ok_or(GenericError::new("Missing dash in the left part of the input."))?;
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let (s_char, s_password) = s_rest.split_once(": ").ok_or(GenericError::new("Missing colon followed by space in the right part of the input."))?;
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Ok(PasswordRule {
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left_value: s_min.parse::<usize>().map_err(|_| GenericError::new("Cannot parse first number."))?,
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right_value: s_max.parse::<usize>().map_err(|_| GenericError::new("Cannot parse second number."))?,
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required_char: s_char.to_string(),
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actual_password: s_password.to_string()
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})
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}
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}
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