This took me 3 days. I had to get a better understanding of O(n) and prime calculations. I was on the right path on my first attempt by reducing the number of calculations in half, but I found out you can reduce the number of calculations exponentially, and that got me a working solution.

So why list rules at all?

And I think you can figure out what the expecteds that I listed are showing. You're a smart guy.

Well, I tried. Guess you got it all figured out.

Also, holy verbosity!!

Seesm these two following rules were just left out:

• If Fox(es) are only in cages then Chicken(s) outside of cages are safe
• If no Fox(es) are present then all Chicken(s) are safe

Examples:

• Expected: '.C.[.............F...]'
• Expected: '.C..[C.]..C....[C]..[C..]'
• Expected: '...C...[C.CC.C....].C.CC'
• Expected: 'C...CCCC[..............F............]CC.C[.].C..'

Seems odd you would just leave these very pertinent rules out.

Agreed. Mostly gibberish.

Yep, that worked. Thank you.

How do you explain this?

Expected: 1
12
1**3, instead got: 1
12
13
Expected: 1
1*2
13
14
15
16
17, instead got: 1
12
13
14
15
16
17
Expected: 1
12
13
14
15
16
17
18
19
110
111
112
113
114
115
116
117
118
119
120, instead got: 1
12
13
14
15
16
17
18
19
110
111
112
113
114
115
116
117
118
119
1*********20