From 7f4517b9e6c01491f7021b4dc11f3a4ef0ced8f2 Mon Sep 17 00:00:00 2001
From: Joshua Smallwood <31932412+smallwoj@users.noreply.github.com>
Date: Tue, 2 Dec 2025 20:07:05 -0600
Subject: [PATCH] feat: solve day 2

---
 Cargo.lock           | 40 +++++++++++++++++---------
 Cargo.toml           |  2 +-
 data/examples/02.txt |  1 +
 src/bin/02.rs        | 68 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 97 insertions(+), 14 deletions(-)
 create mode 100644 data/examples/02.txt
 create mode 100644 src/bin/02.rs

diff --git a/Cargo.lock b/Cargo.lock
index 90137cc..25c8c88 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -23,9 +23,9 @@ version = "0.12.0"
 dependencies = [
  "chrono",
  "dhat",
+ "fancy-regex",
  "itertools",
  "pico-args",
- "regex",
  "tinyjson",
 ]
 
@@ -74,6 +74,21 @@ dependencies = [
  "rustc-demangle",
 ]
 
+[[package]]
+name = "bit-set"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "08807e080ed7f9d5433fa9b275196cfc35414f66a0c79d864dc51a0d825231a3"
+dependencies = [
+ "bit-vec",
+]
+
+[[package]]
+name = "bit-vec"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e764a1d40d510daf35e07be9eb06e75770908c27d411ee6c92109c9840eaaf7"
+
 [[package]]
 name = "bitflags"
 version = "1.3.2"
@@ -143,6 +158,17 @@ version = "1.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "48c757948c5ede0e46177b7add2e67155f70e33c07fea8284df6576da70b3719"
 
+[[package]]
+name = "fancy-regex"
+version = "0.16.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "998b056554fbe42e03ae0e152895cd1a7e1002aec800fdc6635d20270260c46f"
+dependencies = [
+ "bit-set",
+ "regex-automata",
+ "regex-syntax",
+]
+
 [[package]]
 name = "gimli"
 version = "0.28.1"
@@ -329,18 +355,6 @@ dependencies = [
  "bitflags",
 ]
 
-[[package]]
-name = "regex"
-version = "1.12.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "843bc0191f75f3e22651ae5f1e72939ab2f72a4bc30fa80a066bd66edefc24d4"
-dependencies = [
- "aho-corasick",
- "memchr",
- "regex-automata",
- "regex-syntax",
-]
-
 [[package]]
 name = "regex-automata"
 version = "0.4.13"
diff --git a/Cargo.toml b/Cargo.toml
index af508f9..efd1698 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -29,5 +29,5 @@ tinyjson = "2.5.1"
 
 # Solution dependencies
 itertools = "0.14.0"
-regex = "1.12.2"
+fancy-regex = "0.16.2"
 
diff --git a/data/examples/02.txt b/data/examples/02.txt
new file mode 100644
index 0000000..a3f22ef
--- /dev/null
+++ b/data/examples/02.txt
@@ -0,0 +1 @@
+11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124
diff --git a/src/bin/02.rs b/src/bin/02.rs
new file mode 100644
index 0000000..0c5be43
--- /dev/null
+++ b/src/bin/02.rs
@@ -0,0 +1,68 @@
+use fancy_regex::Regex;
+use itertools::Itertools;
+use std::str::FromStr;
+
+advent_of_code::solution!(2);
+
+pub fn part_one(input: &str) -> Option<u64> {
+    input
+        .split(",")
+        .map(|range| {
+            let [start, end] = range.split("-").collect::<Vec<&str>>().try_into().unwrap();
+            let start_num = start.parse().unwrap_or(0);
+            let end_num = end.parse().unwrap_or(0);
+            (start_num..(end_num + 1))
+                .map(|id| {
+                    let mut chars = id.to_string().chars().collect::<Vec<char>>();
+                    let second_chars = chars.split_off(chars.len() / 2);
+                    if chars == second_chars { id } else { 0 }
+                })
+                .sum1()
+                .unwrap_or(0)
+        })
+        .sum1()
+}
+
+pub fn part_two(input: &str) -> Option<u128> {
+    input
+        .split(",")
+        .map(|range| {
+            let [start, end] = range
+                .split("-")
+                .map(|s| s.trim())
+                .collect::<Vec<&str>>()
+                .try_into()
+                .unwrap();
+            let start_num: u128 = u128::from_str(start).unwrap();
+            let end_num: u128 = u128::from_str(end).unwrap();
+            (start_num..(end_num + 1))
+                .map(|id| {
+                    let re = Regex::new(r"^(\d+)\1+$").unwrap();
+                    if re.is_match(&id.to_string()).unwrap_or(false) {
+                        id
+                    } else {
+                        0
+                    }
+                })
+                .sum1()
+                .unwrap_or(0)
+        })
+        .sum1()
+}
+
+#[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(1227775554));
+    }
+
+    #[test]
+    fn test_part_two() {
+        let result = part_two(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(4174379265));
+    }
+}