day 11 pt1

src/bin/11.rs

@@ -5,44 +5,75 @@ use itertools::Itertools;
 advent_of_code::solution!(11);
 
 pub fn part_one(input: &str) -> Option<u32> {
-    let mut stones = input.strip_suffix("\n")?.split(" ").collect_vec();
+    let mut stones = vecify_stones(input);
+    step_stones(&mut stones, 25);
 
-    for step in 0..25 {
-        println!("STEP {step}: {:?}", stones);
-        // stones.clone_from(&process_stones(stones).iter().map(|s| s as &str).collect_vec());
-        // stones = next_step.clone().iter().map(|s| s as &str).collect_vec();
-        for idx in (0..stones.len()).rev() {
-            let stone = stones[idx];
-            let stone_length = stone.len();
-            if stone == "0" {
-                stones[idx] = "1";
-            } else if stone_length % 2 == 0 {
-                let stone_iter = stone.chars().into_iter();
-                // THIS IS BROKEN AND I"M VERY SAD
-                let first_half = stone_iter.by_ref().take(stone_length/2).collect::<String>().as_str();
+    let total_count = stones.len();
+    println!("FINAL STONES: {:?} stones", total_count);
 
-                let second_half = stone.chars().into_iter().skip(stone_length/2).take(stone_length/2).collect::<String>().as_str();
-                stones[idx] = first_half;
-                stones.insert(idx + 1, second_half);
-            } else {
-                stones[idx] = stone.parse::<usize>().unwrap().mul(2024).to_string().as_str();
-            }
-        }
-    }
-
-    println!("FINAL STONES: {:?}", stones);
-    None
+    Some(total_count as u32)
 }
 
 pub fn part_two(input: &str) -> Option<u32> {
     None
 }
 
+fn step_stones(stones: &mut Vec<String>, max_steps: usize) {
+    for _step in 0..max_steps {
+        // println!("STEP #{step}: {:?} stones", stones.len());
+        // stones.clone_from(&process_stones(stones).iter().map(|s| s as &str).collect_vec());
+        // stones = next_step.clone().iter().map(|s| s as &str).collect_vec();
+        for idx in (0..stones.len()).rev() {
+            let stone = &stones[idx];
+            let stone_length = stone.len();
+            if stone == "0" {
+                stones[idx] = String::from("1");
+            } else if stone_length % 2 == 0 {
+                let mut stone_iter = stone.chars().into_iter();
+                let first_half = stone_iter.by_ref().take(stone_length/2).collect::<String>();
+                let second_half = stone_iter.by_ref().take(stone_length/2).collect::<String>().parse::<usize>().unwrap().to_string();
+
+                stones[idx] = first_half;
+                stones.insert(idx + 1, second_half);
+            } else {
+                let new_stone = stone.parse::<usize>().unwrap().mul(2024).to_string();
+                stones[idx] = new_stone;
+            }
+        }
+    }
+}
+
+fn vecify_stones(input: &str) -> Vec<String> {
+    input.strip_suffix("\n").unwrap().split(" ").map(|s| s.to_string()).collect_vec()
+}
 
 #[cfg(test)]
 mod tests {
     use super::*;
 
+    #[test]
+    fn test_step_stones() {
+        let mut stones= vecify_stones("125 17\n");
+
+        step_stones(&mut stones, 1);
+        assert_eq!(stones, vecify_stones("253000 1 7\n"));
+
+        step_stones(&mut stones, 1);
+        assert_eq!(stones, vecify_stones("253 0 2024 14168\n"));
+
+        step_stones(&mut stones, 1);
+        assert_eq!(stones, vecify_stones("512072 1 20 24 28676032\n"));
+
+        step_stones(&mut stones, 1);
+        assert_eq!(stones, vecify_stones("512 72 2024 2 0 2 4 2867 6032\n"));
+
+        step_stones(&mut stones, 1);
+        assert_eq!(stones, vecify_stones("1036288 7 2 20 24 4048 1 4048 8096 28 67 60 32\n"));
+
+        step_stones(&mut stones, 1);
+        assert_eq!(stones, vecify_stones("2097446912 14168 4048 2 0 2 4 40 48 2024 40 48 80 96 2 8 6 7 6 0 3 2\n"));
+    }
+
     #[test]
     fn test_part_one() {
         let result = part_one(&advent_of_code::template::read_file("examples", DAY));