2015 Day 10

Author: BakerNet

README.md

@@ -13,7 +13,7 @@ Solutions for [Advent of Code](https://adventofcode.com/) in [Rust](https://www.
 | [2025](aoc2025) | 14/24 |
 | [2024](aoc2024) | 50/50 |
 | [2023](aoc2023) | 50/50 |
-| [2015](aoc2015) | 18/50 |
+| [2015](aoc2015) | 20/50 |
 
 ---
 

aoc2015/README.md

@@ -15,7 +15,7 @@ Solutions for [Advent of Code](https://adventofcode.com/) in [Rust](https://www.
 | [Day 7](https://adventofcode.com/2024/day/7) | [code](src/bin/07.rs) | ⭐ | ⭐ |
 | [Day 8](https://adventofcode.com/2024/day/8) | [code](src/bin/08.rs) | ⭐ | ⭐ |
 | [Day 9](https://adventofcode.com/2024/day/9) | [code](src/bin/09.rs) | ⭐ | ⭐ |
-| [Day 10](https://adventofcode.com/2024/day/10) | [code](src/bin/10.rs) | _ | _ |
+| [Day 10](https://adventofcode.com/2024/day/10) | [code](src/bin/10.rs) | ⭐ | ⭐ |
 | [Day 11](https://adventofcode.com/2024/day/11) | [code](src/bin/11.rs) | _ | _ |
 | [Day 12](https://adventofcode.com/2024/day/12) | [code](src/bin/12.rs) | _ | _ |
 | [Day 13](https://adventofcode.com/2024/day/13) | [code](src/bin/13.rs) | _ | _ |

aoc2015/data/examples/10.txt

@@ -0,0 +1 @@
+211

aoc2015/src/bin/10.rs

@@ -0,0 +1,50 @@
+advent_of_code::solution!(10);
+
+fn run_n_times(input: &str, n: usize) -> String {
+    let mut curr = input.trim().to_string();
+    let mut new = String::new();
+    for _ in 0..n {
+        let mut chars = curr.chars();
+        let mut curr_char = chars.next().expect("Should never have empty string");
+        let mut curr_count = 1;
+        for c in chars {
+            if c != curr_char {
+                new += &format!("{curr_count}{curr_char}");
+                curr_char = c;
+                curr_count = 1;
+            } else {
+                curr_count += 1;
+            }
+        }
+        curr = new + &format!("{curr_count}{curr_char}");
+        new = String::new();
+    }
+    curr
+}
+
+pub fn part_one(input: &str) -> Option<u64> {
+    let res = run_n_times(input, 40);
+    Some(res.len() as u64)
+}
+
+pub fn part_two(input: &str) -> Option<u64> {
+    let res = run_n_times(input, 50);
+    Some(res.len() as u64)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part_one() {
+        let result = part_one(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(86710));
+    }
+
+    #[test]
+    fn test_part_two() {
+        let result = part_two(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(1227900));
+    }
+}