advent-of-code/2021/08

08

This was super fun and another episode of "I should have gotten my paper out sooner".

As soon as I realized you can take the statistical approach to decode the numbers.

1. Count all characters

This will reveal the mapping for the letters b, e and f, as they appear a unique amount of times.

2. a & c

Both appear 8 times. We find a by looking at the 1 and 7. If we identify 1 (cf) and 7 (afc) we can simply calculate what a is by difference. With a identified c is also determined.

3. d & g

Both appear 7 times. We take the similar approach as in 2.

This ensures a linear time execution.

Solutions

1. 449
2. 968175