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aoc-2022/day7/src/main.rs
2022-12-27 01:46:31 +00:00

84 lines
2.5 KiB
Rust

use std::borrow::BorrowMut;
use petgraph::dot::*;
use petgraph::prelude::*;
use petgraph::*;
fn do_weights(g: &mut Graph<(String, u64), ()>, root_dir: NodeIndex<u32>) {
for edge in g.clone().edges_directed(root_dir, Outgoing) {
let mut target_weight = g.node_weight(edge.target()).unwrap();
if target_weight.1 == 0 {
do_weights(g, edge.target());
target_weight = g.node_weight(edge.target()).unwrap();
}
g.node_weight_mut(root_dir).unwrap().1 += target_weight.1;
}
}
fn main() {
const INPUT: &str = include_str!("../input.txt");
let mut g = DiGraph::<(String, u64), (), u32>::new();
let invalid_index: NodeIndex<u32> = NodeIndex::from(u32::MAX);
let mut curr_dir: NodeIndex<u32> = invalid_index;
let mut root_dir: NodeIndex<u32> = invalid_index;
for line in INPUT.lines() {
if line.starts_with("$ cd") {
let new_dir = &line[5..];
if new_dir == ".." {
curr_dir = g
.edges_directed(curr_dir, Incoming)
.next()
.unwrap()
.source();
} else {
let prev_dir = curr_dir;
curr_dir = g.add_node((new_dir.to_string() + "/", 0));
if prev_dir == invalid_index {
root_dir = curr_dir;
} else {
g.add_edge(prev_dir, curr_dir, ());
}
}
} else if line.starts_with("$ ls") {
continue;
} else {
let (size, name) = line.split_once(' ').unwrap();
if size == "dir" {
continue;
}
let size: u64 = size.parse().unwrap();
let n = g.add_node((name.to_string(), size));
g.add_edge(curr_dir, n, ());
}
}
do_weights(g.borrow_mut(), root_dir);
println!("{:?}\n\n", Dot::with_config(&g, &[Config::EdgeNoLabel]));
let total = g
.node_weights()
.filter(|(n, w)| n.ends_with("/") && *w <= 100000)
.map(|(_, w)| w)
.sum::<u64>();
println!("total: {total}");
let used_space = g.node_weight(root_dir).unwrap().1;
let free_space = 70000000 - used_space;
let need_to_free = 30000000 - free_space;
let delete = g
.node_weights()
.filter(|(n, w)| n.ends_with("/") && *w > need_to_free)
.map(|(_, w)| w)
.min()
.unwrap();
println!("delete size: {delete}");
}