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Day 12: clone a little less

This commit is contained in:
kageru 2021-12-12 13:19:21 +01:00
parent 1e03a430b9
commit 4da3dc4a8b
Signed by: kageru
GPG Key ID: 8282A2BEA4ADA3D2
1 changed files with 11 additions and 11 deletions
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22
2021/src/bin/day12.rs
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@ -1,6 +1,6 @@
#![feature(test)]
extern crate test;
use std::collections::{HashMap, HashSet};
use std::collections::HashMap;
use aoc2021::common::*;
use itertools::Itertools;
@ -37,25 +37,25 @@ fn parse_input(raw: &str) -> Parsed {
}
fn part1(parsed: &Parsed) -> usize {
possible_paths(parsed, &Node::Start, HashSet::new(), false)
possible_paths(parsed, &Node::Start, &Vec::new(), false)
}
fn part2(parsed: &Parsed) -> usize {
possible_paths(parsed, &Node::Start, HashSet::new(), true)
possible_paths(parsed, &Node::Start, &Vec::new(), true)
}
fn possible_paths<'a>(map: &'a Parsed, position: &'a Node<'a>, mut visited: HashSet<&'a Node<'a>>, small_cave_allowed: bool) -> usize {
if matches!(position, &Node::Small(_)) {
visited.insert(position);
}
fn possible_paths<'a>(map: &'a Parsed, position: &'a Node<'a>, visited: &Vec<&'a Node<'a>>, small_cave_allowed: bool) -> usize {
map.get(position)
.unwrap()
.iter()
.map(|p| match p {
Node::Big(_) => possible_paths(map, p, visited.clone(), small_cave_allowed),
Node::Small(_) if !visited.contains(&p) => possible_paths(map, p, visited.clone(), small_cave_allowed),
Node::Small(_) if small_cave_allowed => possible_paths(map, p, visited.clone(), false),
Node::Small(_) | Node::Start => 0,
Node::Big(_) => possible_paths(map, p, visited, small_cave_allowed),
Node::Small(_) if !visited.contains(&p) || small_cave_allowed => {
let mut new_visited = visited.to_owned();
new_visited.push(p);
possible_paths(map, p, &new_visited, !visited.contains(&p) && small_cave_allowed)
}
Node::Start | Node::Small(_) => 0,
Node::End => 1,
})
.sum()