2022 day12/rust: add solution

This commit is contained in:
Xiretza 2022-12-12 06:48:49 +01:00
parent 8eab85c260
commit 20981716c3
4 changed files with 144 additions and 0 deletions

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@ -0,0 +1,10 @@
[package]
name = "rust_2022_12"
version = "0.1.0"
edition = "2021"
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
aoc = { path = "../../../common/rust" }
petgraph = "0.6.2"

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@ -0,0 +1,93 @@
#![warn(clippy::pedantic)]
use std::io::{stdin, Read};
use petgraph::{
algo::k_shortest_path,
graph::{Graph, NodeIndex},
visit::IntoNodeReferences,
};
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum NodeKind {
Start,
End,
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
struct NodeData {
kind: Option<NodeKind>,
height: u32,
}
fn main() {
let mut data = String::new();
stdin().read_to_string(&mut data).unwrap();
// graph of "downhill" edges - edge from A to B means that A is reachable from B
let mut graph = Graph::<NodeData, (), _>::new();
let grid: Vec<Vec<NodeIndex>> = data
.lines()
.map(|line| {
line.chars()
.map(|c| {
let (kind, c) = match c {
'S' => (Some(NodeKind::Start), 'a'),
'E' => (Some(NodeKind::End), 'z'),
c => (None, c),
};
let height = u32::from(c) - u32::from('a');
let data = NodeData { kind, height };
graph.add_node(data)
})
.collect()
})
.collect();
for (x, row) in grid.iter().enumerate() {
for (y, &node_id) in row.iter().enumerate() {
let node = graph[node_id];
let x = i32::try_from(x).unwrap();
let y = i32::try_from(y).unwrap();
let neighbours = [(-1i32, 0), (0, -1), (1, 0), (0, 1)]
.into_iter()
.filter_map(|(dx, dy)| {
let x = usize::try_from(x + dx).ok()?;
let y = usize::try_from(y + dy).ok()?;
grid.get(x)?.get(y)
});
for &neighbour_id in neighbours {
let neighbour = graph[neighbour_id];
if node.height <= (neighbour.height + 1) {
// `node` is reachable from `neighbour`
graph.add_edge(node_id, neighbour_id, ());
}
}
}
}
let end = graph
.node_references()
.find_map(|(id, node)| (node.kind == Some(NodeKind::End)).then_some(id))
.unwrap();
let paths = k_shortest_path(&graph, end, None, 1, |_| 1);
let start = graph
.node_references()
.find_map(|(id, node)| (node.kind == Some(NodeKind::Start)).then_some(id))
.unwrap();
println!("{:?}", paths[&start]);
println!(
"{:?}",
paths
.into_iter()
.filter_map(|(start_id, steps)| (graph[start_id].height == 0).then_some(steps))
.min()
.unwrap()
);
}

40
Cargo.lock generated
View file

@ -192,12 +192,24 @@ version = "1.8.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "90e5c1c8368803113bf0c9584fc495a58b86dc8a29edbf8fe877d21d9507e797"
[[package]]
name = "fixedbitset"
version = "0.4.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "0ce7134b9999ecaf8bcd65542e436736ef32ddca1b3e06094cb6ec5755203b80"
[[package]]
name = "half"
version = "1.8.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "eabb4a44450da02c90444cf74558da904edde8fb4e9035a9a6a4e15445af0bd7"
[[package]]
name = "hashbrown"
version = "0.12.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "8a9ee70c43aaf417c914396645a0fa852624801b24ebb7ae78fe8272889ac888"
[[package]]
name = "hermit-abi"
version = "0.1.19"
@ -207,6 +219,16 @@ dependencies = [
"libc",
]
[[package]]
name = "indexmap"
version = "1.9.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "1885e79c1fc4b10f0e172c475f458b7f7b93061064d98c3293e98c5ba0c8b399"
dependencies = [
"autocfg",
"hashbrown",
]
[[package]]
name = "itertools"
version = "0.10.5"
@ -320,6 +342,16 @@ version = "11.1.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "0ab1bc2a289d34bd04a330323ac98a1b4bc82c9d9fcb1e66b63caa84da26b575"
[[package]]
name = "petgraph"
version = "0.6.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "e6d5014253a1331579ce62aa67443b4a658c5e7dd03d4bc6d302b94474888143"
dependencies = [
"fixedbitset",
"indexmap",
]
[[package]]
name = "plotters"
version = "0.3.4"
@ -545,6 +577,14 @@ dependencies = [
"aoc",
]
[[package]]
name = "rust_2022_12"
version = "0.1.0"
dependencies = [
"aoc",
"petgraph",
]
[[package]]
name = "ryu"
version = "1.0.11"

View file

@ -21,4 +21,5 @@ members = [
"2022/day9/rust",
"2022/day10/rust",
"2022/day11/rust",
"2022/day12/rust",
]