blob: 116557883d05a66575278a8e659b043b8ac3337a (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
|
{-
Copyright (C) 2017 Yuchen Pei.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as
published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU Affero General Public
License along with this program. If not, see
<https://www.gnu.org/licenses/>.
-}
import Data.List.Split (splitOn)
import Data.Map (Map)
import qualified Data.Map as Map
exec :: [[Char]] -> Int -> Int -> Map Char Int -> Int
exec rom n addr regs
| addr >= length rom || addr < 0 = n
| op == "set" = exec rom n (addr + 1) (Map.insert dest val regs)
| op == "sub" = exec rom n (addr + 1) (Map.insert dest (dval - val) regs)
| op == "mul" = exec rom (n + 1) (addr + 1) (Map.insert dest (dval * val) regs)
| op == "jnz" = exec rom n (if dval /= 0 then addr + val else addr + 1) regs
where ins = rom !! addr
op:[dest]:xs = splitOn " " ins
dval = getVal [dest]
val = getVal $ head xs
getVal xs = if head xs `elem` alphabet then regs Map.! (head xs) else read xs
isPrime :: Int -> Bool
isPrime x = and $ ((/=0) . rem x) <$> [2 .. floor $ sqrt $ fromIntegral x]
solve2 = length $ filter (==False) $ isPrime <$> [105700, 105717 .. 122700] -- The last number, 122700 should not be included because according to the assembly code when b == c the program terminates without checking primality of b. But the AOC website only accepted the answer when it is included.
alphabet = ['a'..'h']
initRegs :: Map Char Int
initRegs = Map.fromList $ zip ['a'..'h'] (cycle [0])
solve1 :: [Char] -> Int
solve1 xs = exec (lines xs) 0 0 initRegs
input = "set b 57\nset c b\njnz a 2\njnz 1 5\nmul b 100\nsub b -100000\nset c b\nsub c -17000\nset f 1\nset d 2\nset e 2\nset g d\nmul g e\nsub g b\njnz g 2\nset f 0\nsub e -1\nset g e\nsub g b\njnz g -8\nsub d -1\nset g d\nsub g b\njnz g -13\njnz f 2\nsub h -1\nset g b\nsub g c\njnz g 2\njnz 1 3\nsub b -17\njnz 1 -23"
|
