refactor(2023): simplify day 8 part 2

believer · Dec 8, 2023 · 0e9320b · 0e9320b
1 parent 0a0dedb
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diff --git a/rust/2023/README.md b/rust/2023/README.md
@@ -38,7 +38,7 @@ With the help of [cargo-aoc](https://github.com/gobanos/cargo-aoc) I get automat
 | 5   |   1.27 µs | 238.45 ms\*\* | `-16.72%` / `-98.87%` |              16.85 µs |
 | 6   | 101.59 ns |      15.04 ms |                       | 257.13 ns / 204.78 ns |
 | 7   | 364.18 µs |     359.22 µs |                       | 318.23 µs / 324.96 µs |
-| 8   | 935.78 µs |      15.25 ms |                       |             130.34 µs |
+| 8   | 926.09 µs |       4.47 ms | - / `-70.69%`         |             137.33 µs |
 
 \* compared to first solution<br/>
 \*\* slow, didn't benchmark. Value comes from running the solver.
@@ -50,3 +50,4 @@ With the help of [cargo-aoc](https://github.com/gobanos/cargo-aoc) I get automat
 |   3 | 172.23 µs |        - |    Baseline | [Link](https://github.com/believer/advent-of-code/blob/75a83e31024bbac99a0664f81fce4e13ec1e94af/rust/2023/src/day_03.rs) |
 |   4 |  24.33 µs | 24.32 µs |    Baseline | [Link](https://github.com/believer/advent-of-code/blob/c970c6322d3904048bcf3f30b1052e2916476d73/rust/2023/src/day_04.rs) |
 |   5 |   1.50 µs |  21.22 s |    Baseline | [Link](https://github.com/believer/advent-of-code/blob/39b0904c4921f4ae79963a6df49bb3502ef6b3be/rust/2023/src/day_05.rs) |
+|   8 |         - | 15.25 ms |    Baseline | [Link](https://github.com/believer/advent-of-code/blob/4b96f6e935734f657469b091072282f1c430bcd3/rust/2023/src/day_08.rs) |
diff --git a/rust/2023/src/day_08.rs b/rust/2023/src/day_08.rs
@@ -111,28 +111,34 @@ assert_eq!(solve_part_02(&input_generator(data)), 11188774513823);
 ```"#]
 #[aoc(day8, part2)]
 pub fn solve_part_02(input: &Input) -> i64 {
+    let Input {
+        directions,
+        instructions,
+    } = input;
     let mut all_steps = Vec::new();
-    let start_locations = input
-        .instructions
-        .keys()
-        .filter(|i| i.ends_with('A'))
-        .cloned()
-        .collect::<Vec<String>>();
+    let start_locations =
+        instructions
+            .keys()
+            .filter(|i| i.ends_with('A'))
+            .cloned()
+            .collect::<Vec<String>>();
 
     for start in start_locations {
-        let mut current = start.clone();
+        let mut location = start.clone();
         let mut index = 0;
-        let mut current_direction = input.directions.get(index).unwrap();
+        let mut current_direction = directions.get(index).unwrap();
         let mut steps: i64 = 0;
 
-        while !current.ends_with('Z') {
-            current = match current_direction {
-                Direction::Right => input.instructions.get(&current).unwrap().1.to_string(),
-                Direction::Left => input.instructions.get(&current).unwrap().0.to_string(),
+        while !location.ends_with('Z') {
+            let (left, right) = instructions.get(&location).unwrap();
+
+            location = match current_direction {
+                Direction::Right => right.to_string(),
+                Direction::Left => left.to_string(),
             };
 
-            index = (index + 1) % input.directions.len();
-            current_direction = input.directions.get(index).unwrap();
+            index = (index + 1) % directions.len();
+            current_direction = directions.get(index).unwrap();
             steps += 1;
         }