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author | Yuchen Pei <me@ypei.me> | 2017-12-23 12:08:15 +0100 |
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committer | Yuchen Pei <me@ypei.me> | 2017-12-23 12:08:15 +0100 |
commit | 525a0046b758ba54c5a6b54c14fccd24579064e1 (patch) | |
tree | 8efed5c0cec836b1ea4c3c6c82647c8f1bd7b9c7 /Puzzle23.hs | |
parent | 15d597662b7cd5eb950ecf30ddb452cd1f247bf8 (diff) |
finished Day 23
Diffstat (limited to 'Puzzle23.hs')
-rw-r--r-- | Puzzle23.hs | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/Puzzle23.hs b/Puzzle23.hs new file mode 100644 index 0000000..e00afb2 --- /dev/null +++ b/Puzzle23.hs @@ -0,0 +1,33 @@ +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" |