16411번 - Illiteracy 다국어

Illiteracy is a simple puzzle game created by Le Sio. After the contest, you can play it at https://le-slo.itch.io/illiteracy. The game consists of a sequence of eight icons; the actual icons are very artistic, but for simplicity, we’ll label the icons using a capital letter A—F. Clicking any icon has a unique effect on the other icons, based on which icon is clicked and that icon’s position in the sequence. Most of the icons rotate the type of other icons. A rotation changes an A to a B, B to C, C to D, D to E, E to F, and F back to A.

Here’s what the icons do when you click on one, based on the type of the icon and its position x in the sequence (1 ≤ x ≤ 8):

Given a starting sequence of icons and a target sequence, what is the minimal number of clicks required to transform the starting sequence into the target sequence?

The input consists of exactly two lines of eight characters each. The first line is the starting icon sequence, and the second is the target sequence. Each character on each line is one of the six capital letters A, B, C, D, E, or F.

Output a single integer, the smallest number of icon clicks needed to get from the starting sequence to the target sequence or -1 if it isn’t possible..

For the cases below, we illustrate one possible minimal sequence of clicks to get from the top configuration to the bottom one. The carets indicate which icon on the previous line was clicked to generate the sequence on the following line. The sequence on the left takes 2 clicks; the sequence on the right takes 4 clicks.

ABCDEFCD        DCDAFCBA
   ^               ^
BCDDEFCD        DCEAACBA
     ^                ^
BCEDEFCD        DCEAACBC
                 ^
                DCEAACCC
                  ^
                ECEABCCC