64 lines
1.7 KiB
Rust
64 lines
1.7 KiB
Rust
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use std::error;
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use std::fs::File;
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use std::io::BufRead;
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use std::io::BufReader;
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fn main() -> Result<(), Box<dyn error::Error>> {
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let f = File::open("input.txt")?;
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let reader = BufReader::new(f);
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let mut map = vec![];
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let mut width = 0;
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for line in reader.lines() {
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let line = line?;
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width = line.len();
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map.extend(line.chars().map(|c| c.to_digit(10)).flatten().map(|d| d as usize));
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}
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let width = width;
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let height = map.len() / width;
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let mut visible_count = 0;
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for i in 0..map.len() {
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let line = i / height;
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let column = i % width + 1; // we need + 1 here, because there is no modulo 0
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// println!("line: {}, column: {}, self: {}", line, column, map[i]);
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let left = map[(line * width)..i].iter().max();
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let right = map[i..((line + 1) * width)].iter()
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.enumerate()
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.filter_map(|(j, x)| if (j + i) / height == line && j > 0 { Some(x) } else { None })
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.max();
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// let right = map[(i + 1)..((line + 1) * width)].iter().max();
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let up = map[0..i].iter()
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.enumerate()
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//.inspect(|(j, x)| println!("{j} {x}"))
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.filter_map(|(j, x)| if (j + 1) % width == column { Some(x) } else { None })
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.max();
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let down = map[i..].iter()
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.enumerate()
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.filter_map(|(j, x)| if (i + j + 1) % width == column && j > 0 { Some(x) } else { None })
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.max();
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// println!("left: {:?}, right: {:?}, up: {:?}, down: {:?}", &left, &right, &up, &down);
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for direction_max in vec![left, right, up, down] {
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match direction_max {
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Some(x) if x < &map[i] => {
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visible_count += 1;
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break;
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},
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None => {
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visible_count += 1;
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break;
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},
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_ => ()
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}
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}
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// println!("visible: {visible_count}");
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}
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println!("Found {visible_count} visible trees.");
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Ok(())
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}
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