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82 lines
2.5 KiB
Rust
82 lines
2.5 KiB
Rust
use std::borrow::ToOwned;
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use std::collections::{HashMap, HashSet};
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use std::fs::File;
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use std::io::{BufRead, BufReader};
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use std::iter::FromIterator;
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use std::result::Result::{Err, Ok};
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use std::string::{String, ToString};
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fn main() {
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let file = match File::open("input") {
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Ok(file) => file,
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Err(e) => panic!(e)
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};
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let input_buffer = BufReader::new(&file);
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let edges: Vec<(String, (u32, String))> = input_buffer.lines().map(
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|rline| {
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parse_edge_set(rline.unwrap())
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}
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).flatten().collect();
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let reverse_graph: Vec<(String, (u32, String))> = Vec::from_iter(edges.iter().map(
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|(parent, (count, child))| (child.clone(), (count.clone(), parent.clone()))
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));
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let forward_graph: Vec<(String, (u32, String))> = Vec::from_iter(edges);
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let dn = downstream_nodes("shiny gold".to_string(),
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&reverse_graph,
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HashSet::new());
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println!("Parents: {}", dn.len());
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println!("All bags: {}", upstream_nodes("shiny gold".to_string(), &forward_graph));
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}
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fn parse_edge_set(line: String) -> Vec<(String, (u32, String))> {
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let splot: Vec<&str> = line[0..line.len() - 1].split("contain ").collect();
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let parent = splot[0][0..splot[0].len() - 5 - 1].to_string();
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println!("{}", parent);
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let children: Vec<(u32, String)> = parse_children(splot[1].to_string());
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children.iter().map(|child| (parent.clone(), child.to_owned())).collect()
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}
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fn parse_children(children: String) -> Vec<(u32, String)> {
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children.split(", ")
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.filter_map(parse_child)
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.collect()
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}
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fn parse_child(child: &str) -> Option<(u32, String)> {
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let splot: Vec<&str> = child.split(" ").collect();
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match splot[0].parse() {
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Ok(count) => Some((count, splot[1].to_string() + " " + splot[2])),
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Err(_e) => None
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}
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}
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fn downstream_nodes(node: String,
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rv_graph: &Vec<(String, (u32, String))>,
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mut nodes: HashSet<String>) -> HashSet<String> {
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for (_child, (_count, parent)) in rv_graph.iter().filter(|(c, _p)| *c == node) {
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nodes.insert(parent.clone());
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println!("{}", parent);
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nodes = downstream_nodes(parent.clone(), rv_graph, nodes)
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}
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nodes
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}
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fn upstream_nodes(node: String,
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fw_graph: &Vec<(String, (u32, String))>) -> u32 {
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let mut count = 0;
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for (_parent, (bag_count, child)) in fw_graph.iter().filter(|(p, _c)| *p == node) {
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count += bag_count * (1 + upstream_nodes(child.clone(), fw_graph))
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}
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count
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}
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