59 lines
2.1 KiB
Rust
59 lines
2.1 KiB
Rust
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// Copyright 2022 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: ./part2 < input
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pub mod common;
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use common::Forest;
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fn main() -> Result<(), &'static str> {
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let forest = Forest::from_stdin()?;
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let (x_len, y_len) = forest.dimensions();
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let mut result = 0;
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for y in 0..y_len {
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for x in 0..x_len {
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let line = forest.line(y).unwrap().collect::<Vec<_>>();
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let column = forest.column(x).unwrap().collect::<Vec<_>>();
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let west = Box::new(line[..x].iter().rev().cloned());
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let east = Box::new(line[x + 1..].iter().cloned());
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let north = Box::new(column[..y].iter().rev().cloned());
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let south = Box::new(column[y + 1..].iter().cloned());
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let views: [Box<dyn Iterator<Item = _>>; 4] = [west, east, north, south];
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let tree = forest.tree(x, y).unwrap();
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let mut scenic_score = 1;
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for view in views {
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let mut viewing_distance = 0;
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for t in view {
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match t {
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_ if { t >= &tree } => {
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viewing_distance += 1;
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break;
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}
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_ if { t < &tree } => viewing_distance += 1,
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_ => break,
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}
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}
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scenic_score *= viewing_distance;
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}
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result = usize::max(result, scenic_score);
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}
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}
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println!("{result}");
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Ok(())
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}
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