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Day 10 - Part 2

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Signed-off-by: Anthony Oteri <anthony.oteri@gmail.com>
This commit is contained in:
Anthony Oteri
2023-12-11 16:18:08 -05:00
parent 2a950bdcb4
commit 74b79ec793
4 changed files with 238 additions and 5 deletions
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day-10/src/part2.rs
+209 -5
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@@ -1,18 +1,222 @@
use crate::error::AocError;
use std::collections::BTreeMap;
#[derive(Debug, Clone, Eq, PartialEq, Default, Ord, PartialOrd)]
struct Point {
row: i32,
col: i32,
}
#[derive(Debug, Clone, Eq, PartialEq, Default)]
struct Pipe {
input: Point,
output: Point,
}
#[derive(Debug, Clone, Eq, PartialEq)]
enum Tile {
Vertical(Pipe),
Horizontal(Pipe),
NorthEast(Pipe),
NorthWest(Pipe),
SouthWest(Pipe),
SouthEast(Pipe),
Ground,
Start,
}
fn parse(input: &str) -> BTreeMap<Point, Tile> {
let grid = input
.lines()
.enumerate()
.flat_map(|(row, line)| {
line.chars().enumerate().map(move |(col, c)| {
let pos = Point {
row: row as i32,
col: col as i32,
};
let tile = match c {
'|' => Tile::Vertical(Pipe {
input: Point {
row: pos.row - 1,
col: pos.col,
},
output: Point {
row: pos.row + 1,
col: pos.col,
},
}),
'-' => Tile::Horizontal(Pipe {
input: Point {
row: pos.row,
col: pos.col - 1,
},
output: Point {
row: pos.row,
col: pos.col + 1,
},
}),
'L' => Tile::NorthEast(Pipe {
input: Point {
row: pos.row - 1,
col: pos.col,
},
output: Point {
row: pos.row,
col: pos.col + 1,
},
}),
'J' => Tile::NorthWest(Pipe {
input: Point {
row: pos.row - 1,
col: pos.col,
},
output: Point {
row: pos.row,
col: pos.col - 1,
},
}),
'7' => Tile::SouthWest(Pipe {
input: Point {
row: pos.row + 1,
col: pos.col,
},
output: Point {
row: pos.row,
col: pos.col - 1,
},
}),
'F' => Tile::SouthEast(Pipe {
input: Point {
row: pos.row + 1,
col: pos.col,
},
output: Point {
row: pos.row,
col: pos.col + 1,
},
}),
'.' => Tile::Ground,
'S' => Tile::Start,
_ => panic!("Unknown tile: {}", c),
};
(pos, tile)
})
})
.collect::<BTreeMap<Point, Tile>>();
grid
}
#[tracing::instrument]
pub fn process(input: &str) -> miette::Result<u64, AocError> {
Ok(0)
let grid = parse(input);
let mut main_loop = BTreeMap::default();
let start: &Point = grid
.iter()
.find(|(_, tile)| **tile == Tile::Start)
.map(|(pos, _)| pos)
.unwrap();
let start_connects: Vec<&Point> = grid
.iter()
.filter(|(_, tile)| match tile {
Tile::Vertical(pipe) => pipe.input == *start || pipe.output == *start,
Tile::Horizontal(pipe) => pipe.input == *start || pipe.output == *start,
Tile::NorthEast(pipe) => pipe.input == *start || pipe.output == *start,
Tile::NorthWest(pipe) => pipe.input == *start || pipe.output == *start,
Tile::SouthWest(pipe) => pipe.input == *start || pipe.output == *start,
Tile::SouthEast(pipe) => pipe.input == *start || pipe.output == *start,
_ => false,
})
.map(|(pos, _)| pos)
.collect();
let mut current = *start_connects.first().unwrap();
let mut prev = start;
while current != start {
let tile = grid.get(current).unwrap();
match tile {
Tile::Vertical(p)
| Tile::Horizontal(p)
| Tile::NorthEast(p)
| Tile::NorthWest(p)
| Tile::SouthEast(p)
| Tile::SouthWest(p) => {
if p.input == *prev {
prev = current;
current = &p.output;
main_loop.insert(current, tile);
main_loop.insert(prev, tile);
} else {
prev = current;
current = &p.input;
main_loop.insert(current, tile);
main_loop.insert(prev, tile);
}
}
_ => panic!("Unknown tile: {:?}", tile),
}
}
Ok(grid
.iter()
.filter(|(pos, _)| !main_loop.contains_key(pos))
.filter_map(|(pos, _)| {
let tiles_in_row = main_loop.keys().filter(|p| p.row == pos.row);
let count_west = tiles_in_row
.clone()
.filter(|t| {
matches!(
main_loop.get(*t),
Some(Tile::Vertical(_))
| Some(Tile::Start)
| Some(Tile::SouthEast(_))
| Some(Tile::SouthWest(_))
) && t.col < pos.col
})
.count();
let count_east = tiles_in_row
.clone()
.filter(|t| {
matches!(
main_loop.get(*t),
Some(Tile::Vertical(_))
| Some(Tile::Start)
| Some(Tile::SouthEast(_))
| Some(Tile::SouthWest(_))
) && t.col > pos.col
})
.count();
if count_west % 2 != 0 && (count_east % 2 != 0 || count_east != 0) {
Some(1)
} else {
None
}
})
.count() as u64)
}
#[cfg(test)]
mod tests {
use super::*;
use rstest::rstest;
#[test_log::test]
fn test_process() -> miette::Result<()> {
let input = include_str!("../test-input.txt");
assert_eq!(0, process(input)?);
#[test_log::test(rstest)]
#[case("test-input3.txt", 4)]
#[case("test-input4.txt", 8)]
#[case("test-input5.txt", 10)]
fn test_process(#[case] filename: &str, #[case] expected: usize) -> miette::Result<()> {
let input =
String::from_utf8_lossy(&std::fs::read(std::path::Path::new(filename)).unwrap())
.parse::<String>()
.unwrap();
assert_eq!(expected, process(&input)? as usize);
Ok(())
}
}
day-10/test-input3.txt
+9
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@@ -0,0 +1,9 @@
...........
.S-------7.
.|F-----7|.
.||.....||.
.||.....||.
.|L-7.F-J|.
.|..|.|..|.
.L--J.L--J.
...........
day-10/test-input4.txt
+10
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@@ -0,0 +1,10 @@
.F----7F7F7F7F-7....
.|F--7||||||||FJ....
.||.FJ||||||||L7....
FJL7L7LJLJ||LJ.L-7..
L--J.L7...LJS7F-7L7.
....F-J..F7FJ|L7L7L7
....L7.F7||L7|.L7L7|
.....|FJLJ|FJ|F7|.LJ
....FJL-7.||.||||...
....L---J.LJ.LJLJ...
day-10/test-input5.txt
+10
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@@ -0,0 +1,10 @@
FF7FSF7F7F7F7F7F---7
L|LJ||||||||||||F--J
FL-7LJLJ||||||LJL-77
F--JF--7||LJLJ7F7FJ-
L---JF-JLJ.||-FJLJJ7
|F|F-JF---7F7-L7L|7|
|FFJF7L7F-JF7|JL---7
7-L-JL7||F7|L7F-7F7|
L.L7LFJ|||||FJL7||LJ
L7JLJL-JLJLJL--JLJ.L