2 files changed, 237 insertions, 0 deletions
diff --git a/14/src/.main.rs.swo b/14/src/.main.rs.swo
new file mode 100644
index 0000000..dcf9781
--- /dev/null
+++ b/14/src/.main.rs.swo
Binary files differdiff --git a/14/src/main.rs b/14/src/main.rs
new file mode 100644
index 0000000..481b785
--- /dev/null
+++ b/14/src/main.rs
@@ -0,0 +1,237 @@
+use advent_lib::prelude::*;
+
+use std::collections::HashMap;
+
+
+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::group_lines_by_blanks(
+    advent_lib::read_lines_file(&filename)?);
+
+  let template = input[0][0].clone();
+
+  let mut rules: HashMap<(char, char),char> = HashMap::new();
+  for line in &input[1]{
+    let words: Vec<&str> = line.split_whitespace().collect();
+    let lhs: Vec<char> = words[0].chars().collect();
+    let rhs: Vec<char> = words[2].chars().collect();
+    let left = lhs[0];
+    let right = lhs[1];
+    let inserted = rhs[0];
+    rules.insert((left, right), inserted);
+  }
+
+  let mut pairized = pairize(&template);
+  for _ in 0 .. 10 {
+    pairized = pairized_iterate(&pairized, &rules);
+  }
+  let answer = pairized_score(&template, &pairized);
+  println!("{}", answer);
+
+  for _ in 10 .. 40 {
+    pairized = pairized_iterate(&pairized, &rules);
+  }
+  let answer = pairized_score(&template, &pairized);
+  println!("{}", answer);
+
+  Ok(())
+}
+
+
+#[allow(dead_code)]
+fn iterate(template: &str, rules: &HashMap<(char, char), char>) -> String {
+  let mut result = String::new();
+  let length = template.len();
+
+  for i in 0 .. length - 1 {
+    let left = template.chars().nth(i).unwrap();
+    let right = template.chars().nth(i + 1).unwrap();
+    let inserted = rules.get(&(left, right));
+
+    result.push(left);
+
+    match inserted {
+      None => { }
+      Some(c) => {
+        result.push(*c);
+      }
+    }
+
+    if i == length - 2 {
+      result.push(right);
+    }
+  }
+
+  result
+}
+
+
+#[allow(dead_code)]
+fn score(template: &str) -> i64 {
+  let mut buckets = HashMap::new();
+
+  for c in template.chars() {
+    let value = buckets.get(&c);
+    match value {
+      None => {
+        buckets.insert(c, 1);
+      }
+      Some(total) => {
+        let new_total = total + 1;
+        buckets.insert(c, new_total);
+      }
+    }
+  }
+
+  let mut min_value = None;
+  let mut max_value = None;
+  for (_, value) in &buckets {
+    match min_value {
+      None => {
+        min_value = Some(value);
+      }
+      Some(old_value) => {
+        if value < old_value {
+          min_value = Some(value);
+        }
+      }
+    }
+
+    match max_value {
+      None => {
+        max_value = Some(value);
+      }
+      Some(old_value) => {
+        if value > old_value {
+          max_value = Some(value);
+        }
+      }
+    }
+  }
+
+  max_value.unwrap() - min_value.unwrap()
+}
+
+
+fn pairize(template: &str) -> HashMap<(char, char), usize> {
+  let mut result: HashMap<(char, char), usize> = HashMap::new();
+
+  for i in 0 .. template.len() - 1 {
+    let left = template.chars().nth(i).unwrap();
+    let right = template.chars().nth(i + 1).unwrap();
+    let key = (left, right);
+
+    match result.get(&key) {
+      None => {
+        result.insert(key, 1);
+      }
+      Some(count) => {
+        let new_count = count + 1;
+        result.insert(key, new_count);
+      }
+    }
+  }
+
+  result
+}
+
+
+fn pairized_iterate(
+    pairized: &HashMap<(char, char), usize>,
+    rules: &HashMap<(char, char), char>)
+  -> HashMap<(char, char), usize>
+{
+  let mut result: HashMap<(char, char), usize> = HashMap::new();
+
+  for (key, value) in pairized {
+    match rules.get(&key) {
+      None => {
+        result.insert(key.clone(), *value);
+      }
+      Some(inserted) => {
+        let (left, right) = key;
+        let left_key = (*left, *inserted);
+        let right_key = (*inserted, *right);
+
+        match result.get(&left_key) {
+          None => {
+            result.insert(left_key, *value);
+          }
+          Some(old_value) => {
+            let new_value = old_value + value;
+            result.insert(left_key, new_value);
+          }
+        }
+
+        match result.get(&right_key) {
+          None => {
+            result.insert(right_key, *value);
+          }
+          Some(old_value) => {
+            let new_value = old_value + value;
+            result.insert(right_key, new_value);
+          }
+        }
+      }
+    }
+  }
+
+  result
+}
+
+
+fn pairized_score(original: &str, pairized: &HashMap<(char, char), usize>)
+  -> usize
+{
+  let mut buckets = HashMap::new();
+
+  let leftmost = original.chars().nth(0).unwrap();
+  buckets.insert(leftmost, 1);
+
+  for ((_, c), value) in pairized {
+    match buckets.get(&c) {
+      None => {
+        buckets.insert(*c, *value);
+      }
+      Some(total) => {
+        let new_total = total + value;
+        buckets.insert(*c, new_total);
+      }
+    }
+  }
+
+  let mut min_value = None;
+  let mut max_value = None;
+  for (_, value) in &buckets {
+    match min_value {
+      None => {
+        min_value = Some(value);
+      }
+      Some(old_value) => {
+        if value < old_value {
+          min_value = Some(value);
+        }
+      }
+    }
+
+    match max_value {
+      None => {
+        max_value = Some(value);
+      }
+      Some(old_value) => {
+        if value > old_value {
+          max_value = Some(value);
+        }
+      }
+    }
+  }
+
+  max_value.unwrap() - min_value.unwrap()
+}
+