From 99cde16ca61aeca11930cfed4c65a58d38fca5cb Mon Sep 17 00:00:00 2001
From: Jos van Goor <Jos van Goor>
Date: Sat, 6 Dec 2025 15:31:49 +0100
Subject: [PATCH] Advent 2025 Day 2 Part 2

---
 advent_of_code_2025/src/day2/part2.rs | 22 +++++++++++++++++-----
 advent_of_code_2025/src/main.rs       |  4 ++--
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/advent_of_code_2025/src/day2/part2.rs b/advent_of_code_2025/src/day2/part2.rs
index 804656e..5d9fa25 100644
--- a/advent_of_code_2025/src/day2/part2.rs
+++ b/advent_of_code_2025/src/day2/part2.rs
@@ -14,14 +14,26 @@ pub fn solve(input: &str) {
 
     for range in ranges {
         for idx in range.start..range.end {
-            let as_str = format!("{idx}");
+            let id = format!("{idx}");
+            let pattern_max_len = id.len() / 2;
+            // println!("id: {id}, len: {}, pattern_max_len: {pattern_max_len}", id.len());
+            
+            for pattern_len in 1..=pattern_max_len {
+                if id.len() % pattern_len != 0 {
+                    continue;
+                }
+                
+                let repeats = id.len() / pattern_len;
+                let pattern = id[..pattern_len].repeat(repeats);
 
-            if as_str.len() % 2 == 0  && as_str[..as_str.len() / 2] == as_str[as_str.len() / 2..] {
-                // println!("invalid found: {as_str}");
-                sum_of_invalids += idx;
+                if pattern == id {
+                    sum_of_invalids += idx;
+                    // println!("invalid pattern found: {id} (pattern: {})", &pattern[..pattern_len]);
+                    break
+                }
             }
         }
     }
 
-    println!("Part 1: {sum_of_invalids}");
+    println!("Part 2: {sum_of_invalids}");
 }
\ No newline at end of file
diff --git a/advent_of_code_2025/src/main.rs b/advent_of_code_2025/src/main.rs
index 3c394c4..6f6e5c7 100644
--- a/advent_of_code_2025/src/main.rs
+++ b/advent_of_code_2025/src/main.rs
@@ -1,5 +1,5 @@
 use paste::paste;
 mod utility;
 
-solve_day!{1}
-// test_day!{1}
+solve_day!{2}
+// test_day!{2}