From 83e957d5f94c540f36b9a6b200d17ef629dd1c57 Mon Sep 17 00:00:00 2001
From: George Thomas <georgefsthomas@gmail.com>
Date: Fri, 19 Dec 2025 15:14:39 +0000
Subject: [PATCH] Fix day 3 error case

This doesn't actually matter for the input data given, but it ensures we get the right error when the battery list is too short, instead of unwrapping.
---
 rust/puzzles/day3.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/rust/puzzles/day3.rs b/rust/puzzles/day3.rs
index 1e05ff0..fda7e32 100644
--- a/rust/puzzles/day3.rs
+++ b/rust/puzzles/day3.rs
@@ -52,6 +52,9 @@ fn max_batteries(n: usize, v: &[u8]) -> Option<Vec<u8>> {
     let mut remaining = n;
     let mut slice = v;
     while remaining > 0 {
+        if slice.len() - remaining + 1 == 0 {
+            return None;
+        }
         let (b, i) = find_max(&slice[..slice.len() - remaining + 1]);
         result.push(b);
         remaining -= 1;