day12 part 1

input/day12.txt

@@ -0,0 +1,34 @@
+initial state: ..##.#######...##.###...#..#.#.#..#.##.#.##....####..........#..#.######..####.#.#..###.##..##..#..#
+
+#..#. => .
+..#.. => .
+..#.# => #
+##.#. => .
+.#... => #
+#.... => .
+##### => #
+.#.## => .
+#.#.. => .
+#.### => #
+.##.. => #
+##... => .
+#...# => #
+####. => #
+#.#.# => .
+#..## => .
+.#### => .
+...## => .
+..### => #
+.#..# => .
+##..# => #
+.#.#. => .
+..##. => .
+###.. => .
+###.# => #
+#.##. => #
+..... => .
+.##.# => #
+....# => .
+##.## => #
+...#. => #
+.###. => .

src/main.rs

@@ -1,4 +1,4 @@
 fn main() {
-    // aoc_2018::tasks::day11::task1();
-    aoc_2018::tasks::day11::task2_fast();
+    aoc_2018::tasks::day12::task1();
+    // aoc_2018::tasks::day11::task2_fast();
 }

src/tasks/day12.rs

@@ -0,0 +1,54 @@
+use crate::utils;
+use std::collections::HashMap;
+use std::ops::Add;
+
+pub fn task1() {
+    let input = utils::read_file("input/day12.txt");
+    let mut input = input.lines();
+    let num_generations = 20;
+
+    let mut state: Vec<char> = "."
+        .repeat(num_generations)
+        .add(&input.next().unwrap()[15..])
+        .add(&".".repeat(num_generations + 2))
+        .chars()
+        .collect();
+
+    let mut transformations: HashMap<String, char> = HashMap::new();
+
+    input.next();
+    for line in input {
+        let key = line.split(" => ").nth(0).unwrap();
+        transformations.insert(key.to_string(), line.chars().last().unwrap());
+    }
+
+    for _ in 0..num_generations {
+        println!("{}", state.iter().collect::<String>());
+        let mut new_state = state.clone();
+        for (i, c) in new_state[2..state.len() - 2].iter_mut().enumerate() {
+            let next = transformations.get(&state[i..i + 5].iter().collect::<String>());
+            if let Some(cc) = next {
+                *c = *cc;
+            } else {
+                *c = '.';
+            }
+        }
+        state = new_state;
+    }
+
+    println!("{}", state.iter().collect::<String>());
+
+    let sum: isize = state
+        .iter()
+        .enumerate()
+        .map(|(i, c)| {
+            if *c == '#' {
+                i as isize - (num_generations as isize)
+            } else {
+                0
+            }
+        })
+        .sum();
+
+    println!("Result: {}", sum);
+}

src/tasks/mod.rs

@@ -9,3 +9,4 @@ pub mod day08;
 pub mod day09;
 pub mod day10;
 pub mod day11;
+pub mod day12;