1 files changed, 99 insertions, 0 deletions
diff --git a/07/src/main.rs b/07/src/main.rs
new file mode 100644
index 0000000..e8e12b5
--- /dev/null
+++ b/07/src/main.rs
@@ -0,0 +1,99 @@
+use advent_lib::prelude::*;
+
+use std::collections::BTreeMap;
+use std::collections::BTreeSet;
+
+
+fn main() -> Result<()> {
+  let mut args = std::env::args();
+  if args.len() != 2 {
+    eprintln!("Usage: advent input");
+  }
+  let _ = args.next();
+  let filename = args.next().unwrap();
+
+  let input = advent_lib::read_lines_file(&filename)?;
+
+  let mut rules: BTreeMap<String, BTreeSet<(i64, String)>> =
+      BTreeMap::new();
+
+  for line in &input {
+    let mut words = Vec::new();
+    for word in line.split(' ') {
+      words.push(word);
+    }
+
+    let key = two_words(words[0], words[1]);
+    let mut value = BTreeSet::new();
+
+    if words[4] != "no" {
+      let mut i = 4;
+      while i + 2 < words.len() {
+        let quantity = words[i].parse::<i64>()?;
+        let color = two_words(words[i+1], words[i+2]);
+        value.insert((quantity, color));
+        i += 4;
+      }
+    }
+
+    rules.insert(key, value);
+  }
+
+  let mut closure: BTreeSet<String> = BTreeSet::new();
+
+  for (container, rhs) in rules.iter() {
+    for (_, containee) in rhs.iter() {
+      if containee == "shiny gold" {
+        closure.insert(container.to_string());
+      }
+    }
+  }
+
+  loop {
+    let mut added_any = false;
+    for (container, rhs) in rules.iter() {
+      if closure.contains(container) {
+        continue;
+      }
+
+      for (_, containee) in rhs.iter() {
+        if closure.contains(containee) {
+          closure.insert(container.to_string());
+          added_any = true;
+        }
+      }
+    }
+
+    if !added_any {
+      break;
+    }
+  }
+
+  println!("{}", closure.len());
+
+  println!("{}", recursive_count(&rules, "shiny gold".to_string()) - 1);
+
+  Ok(())
+}
+
+
+fn two_words(a: &str, b: &str) -> String {
+  let mut result = String::new();
+  result.push_str(a);
+  result.push_str(" ");
+  result.push_str(b);
+  result
+}
+
+
+fn recursive_count(rules: &BTreeMap<String, BTreeSet<(i64, String)>>, container: String) -> i64 {
+  let mut sum = 1;
+
+  let rhs: &BTreeSet<(i64, String)> = rules.get(&container).unwrap();
+  for (quantity, containee) in rhs.iter() {
+    let count_below = recursive_count(rules, containee.to_string());
+    sum += quantity * count_below;
+  }
+
+  sum
+}