58 lines
1.7 KiB
Rust
58 lines
1.7 KiB
Rust
// Copyright 2023 Christian Ulrich
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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//
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// usage: ./part1 < input
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use std::io;
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pub struct CalibrationValues {
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inner: Vec<Vec<char>>,
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}
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impl CalibrationValues {
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pub fn from_stdin() -> Result<Self, &'static str> {
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let mut values = vec![];
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for line in io::stdin().lines() {
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let digits = line
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.unwrap()
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.chars()
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.filter(|c| c.is_digit(10))
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.collect::<Vec<_>>();
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if digits.len() > 0 {
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values.push(digits);
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}
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}
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Ok(Self { inner: values })
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}
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pub fn iter(&mut self) -> std::slice::Iter<'_, Vec<char>> {
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self.inner.iter()
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}
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}
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fn main() -> Result<(), &'static str> {
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let mut values = CalibrationValues::from_stdin()?;
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let mut sum = 0;
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for digits in values.iter() {
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sum += [*digits.first().unwrap(), *digits.last().unwrap()]
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.iter()
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.collect::<String>()
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.parse::<u32>()
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.map_err(|_| "cannot parse calibration value")?;
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}
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println!("{sum}");
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Ok(())
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}
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