56 lines
1.5 KiB
Rust
56 lines
1.5 KiB
Rust
---cargo
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---
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static CONTENT: &'static str = include_str!("./inputs/04_1.txt");
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static GRID_OFFSETS: [(isize, isize); 8] = [(-1, -1), (0, -1), (1, -1), (-1, 0), (1, 0), (-1, 1), (0, 1), (1, 1)];
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#[derive(Debug, PartialEq, Clone)]
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enum Cell {
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Empty,
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PRoll,
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}
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fn main() {
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let mut grid: Vec<_> = CONTENT.lines().map(|l| l.trim()).filter(|l| !l.is_empty()).map(|l| {
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l.chars().map(|c| match c {
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'.' => Cell::Empty,
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'@' => Cell::PRoll,
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other => unreachable!("Unexpected Input {:?}", other),
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}).collect::<Vec<_>>()
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}).collect();
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let mut result = 0;
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loop {
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let mut to_remove = Vec::new();
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for (y, row) in grid.iter().enumerate() {
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for (x, cell) in row.iter().enumerate() {
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if cell != &Cell::PRoll {
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continue;
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}
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let neighbours = GRID_OFFSETS.iter().filter_map(|(xoff, yoff)| Some((x.checked_add_signed(*xoff)?, y.checked_add_signed(*yoff)?))).filter_map(|(x, y)| {
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let cell = grid.get(y)?.get(x)?;
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Some((x, y, cell.clone()))
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}).filter(|(_, _, c)| c == &Cell::PRoll).count();
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if neighbours < 4 {
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result += 1;
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to_remove.push((x, y));
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}
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}
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}
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if to_remove.is_empty() {
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break;
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}
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for (x, y) in to_remove {
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grid[y][x] = Cell::Empty;
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}
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}
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println!("Result: {}", result);
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}
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