Add day 6 solutions. Both, naive and more elaborate.

The naive implementation uses simple ring buffers and scales linearly
with the number of days needed.
The matrix based implementation uses matrix multiplication (implemented
in a brain-dead way inline here) and has the same scaling behaviour,
however implementing it showed that the matrix is correct.
The closed form is, well, a closed form based on the matrix based
solution, but working in the matrix' Eigenspace.

1 files changed, 2 insertions, 0 deletions

diff --git a/Cargo.toml b/Cargo.toml
index 2938a76..1498d06 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,5 +9,7 @@ edition = "2021"
 aoc-runner = "0.3"
 aoc-runner-derive = "0.3"
 
+boxed_array_ringbuffer = { path = '../boxed_array_ringbuffer', version = '*'}
+
 [profile.dev]
 opt-level=3