2023-08 in haskell

5 files changed, 929 insertions, 0 deletions

diff --git a/2023/08-Haunted_Wasteland/example b/2023/08-Haunted_Wasteland/example
new file mode 100644
index 0000000..9029a1b
--- /dev/null
+++ b/2023/08-Haunted_Wasteland/example
@@ -0,0 +1,9 @@
+RL
+
+AAA = (BBB, CCC)
+BBB = (DDD, EEE)
+CCC = (ZZZ, GGG)
+DDD = (DDD, DDD)
+EEE = (EEE, EEE)
+GGG = (GGG, GGG)
+ZZZ = (ZZZ, ZZZ)
diff --git a/2023/08-Haunted_Wasteland/example2 b/2023/08-Haunted_Wasteland/example2
new file mode 100644
index 0000000..5b3fa58
--- /dev/null
+++ b/2023/08-Haunted_Wasteland/example2
@@ -0,0 +1,10 @@
+LR
+
+11A = (11B, XXX)
+11B = (XXX, 11Z)
+11Z = (11B, XXX)
+22A = (22B, XXX)
+22B = (22C, 22C)
+22C = (22Z, 22Z)
+22Z = (22B, 22B)
+XXX = (XXX, XXX)
diff --git a/2023/08-Haunted_Wasteland/first.hs b/2023/08-Haunted_Wasteland/first.hs
new file mode 100644
index 0000000..54b773f
--- /dev/null
+++ b/2023/08-Haunted_Wasteland/first.hs
@@ -0,0 +1,74 @@
+-- requires cabal install --lib megaparsec parser-combinators
+module Main (main) where
+
+import Control.Applicative.Permutations
+import Control.Monad (void, when)
+import Data.Char qualified as C
+import Data.Either
+import Data.Functor
+import Data.List qualified as L
+import Data.Map qualified as M
+import Data.Maybe
+import Data.Set qualified as S
+import Data.Void (Void)
+import Text.Megaparsec
+import Text.Megaparsec.Char
+
+import Debug.Trace
+
+exampleExpectedOutput = 2
+
+data Direction = L | R deriving (Eq, Show)
+type Branch = (String, String)
+type Map = M.Map String Branch
+data Input = Input [Direction] Map deriving Show
+
+type Parser = Parsec Void String
+
+parseDirection :: Parser Direction
+parseDirection = char 'L' $> L
+             <|> char 'R' $> R
+
+parseNode :: Parser String
+parseNode = some letterChar
+
+parseBranch :: Parser Branch
+parseBranch = (,) <$> (char '(' *> parseNode)
+                  <*> (string ", " *> parseNode <* char ')')
+
+parseMapElt :: Parser (String, Branch)
+parseMapElt = (,) <$> (parseNode <* string " = ")
+                  <*> (parseBranch <* eol)
+
+parseInput' :: Parser Input
+parseInput' = Input <$> some parseDirection <* eol <* eol
+                    <*> (M.fromList <$> some parseMapElt <* eof)
+
+parseInput :: String -> IO Input
+parseInput filename = do
+  input <- readFile filename
+  case runParser parseInput' filename input of
+    Left bundle -> error $ errorBundlePretty bundle
+    Right input' -> return input'
+
+compute :: Input -> Int
+compute (Input directions m) = compute' "AAA" 0
+  where
+    compute' :: String -> Int -> Int
+    compute' node i | node == "ZZZ" = i
+                    | otherwise = compute' (nextOne node) (i+1)
+      where
+        nextOne :: String -> String
+        nextOne = next . (m M.!)
+        next :: Branch -> String
+        next | directions L.!! (i `mod` l) == L = fst
+             | otherwise = snd
+    l = length directions
+
+main :: IO ()
+main = do
+  example <- parseInput "example"
+  let exampleOutput = compute example
+  when  (exampleOutput /= exampleExpectedOutput)  (error $ "example failed: got " ++ show exampleOutput ++ " instead of " ++ show exampleExpectedOutput)
+  input <- parseInput "input"
+  print $ compute input
diff --git a/2023/08-Haunted_Wasteland/input b/2023/08-Haunted_Wasteland/input
new file mode 100644
index 0000000..90be217
--- /dev/null
+++ b/2023/08-Haunted_Wasteland/input
@@ -0,0 +1,760 @@
+LRRRLRRLRRLRRLLLRRRLRRLLRRRLRLLLRRLRLRLRLRLRLRLRRRLLLRRLRRRLRLLRRRLRRRLRRRLLRRRLRLRRRLRRLRRRLLRLLRLLRRRLRRRLRRLRLRLLRLRRLRRRLRRRLRLRLRLRRLRLRLLLRRRLRLRLRRRLRRRLRRRLRLLLRRLRLRLRLRLLLRRRLRRLRRLRLRLRRRLRLRRRLRRRLRRRLRLRRRLLLRRLRRRLRRLLRLRRLRRLRRRLLLRRLRRLRRLRLRRRLLLRLRRRR
+
+PND = (LHJ, NLX)
+KPD = (HMV, DLD)
+GBD = (QFL, XNG)
+QGL = (BPR, XTJ)
+XTJ = (VCQ, TBJ)
+BQT = (NXD, SCD)
+QJK = (TKT, CTC)
+MMP = (VMB, NGD)
+DDN = (JRC, JRC)
+CFM = (HCK, CCB)
+FNX = (XHK, GCP)
+JFP = (XMD, QTS)
+LJL = (DCT, PGF)
+TPH = (GLJ, DBV)
+BNH = (JCB, KBQ)
+KJM = (GBD, JDP)
+CGX = (VGJ, VCP)
+LFK = (XSM, SHM)
+RSP = (GRS, SRF)
+CMH = (TRC, JXX)
+FXX = (FRM, QVN)
+MSS = (TCG, CQC)
+DFC = (MSS, FQM)
+LVJ = (JJG, TFC)
+FRK = (NDQ, CDN)
+BCF = (TCF, MFR)
+KGJ = (MVN, VKK)
+FHK = (MLK, PCS)
+VFP = (QGX, NHF)
+FMR = (MKH, QKN)
+XRG = (DJB, MXG)
+VMG = (JNC, XCN)
+MSC = (KBR, HPP)
+TFC = (GXJ, JSF)
+PSV = (BPN, QTG)
+CPK = (HMH, MRQ)
+SRF = (KMV, BSM)
+KVV = (DHF, PGX)
+PJL = (JHL, CPK)
+MVS = (VRJ, NTP)
+VMB = (XBQ, PVS)
+DXS = (RKB, KPD)
+BJX = (MCK, LCL)
+BNZ = (QRF, PQL)
+SJT = (DDD, RMR)
+BBS = (MTL, MTL)
+RMG = (CDN, NDQ)
+KFG = (XNS, HGP)
+BPN = (RKQ, GVC)
+KCN = (CVH, XCH)
+JPS = (VMG, RTR)
+LDX = (LVF, BSD)
+PSQ = (BKM, MGZ)
+GXJ = (JHM, LKQ)
+VPC = (LBJ, HDD)
+DDB = (PNL, NFH)
+TVD = (PJL, FMJ)
+TQH = (PCX, JSQ)
+MPP = (CHR, XCP)
+CRQ = (FKG, JQJ)
+PVT = (NMK, HKH)
+DSH = (LDN, BMR)
+XND = (NPQ, BKV)
+SHM = (MSC, JNS)
+FLV = (TVT, HSM)
+GJN = (FTC, XFX)
+HKX = (BCF, FHJ)
+DBJ = (TLN, CVP)
+CVR = (KFC, LQP)
+VRJ = (QMB, XLV)
+LSS = (MCK, LCL)
+GPH = (TSV, FKN)
+MLF = (BBS, BBS)
+CTN = (MML, SXC)
+NMR = (DCS, XQN)
+VNP = (SFF, QSD)
+TBJ = (XPG, XHV)
+VCP = (SCV, TDB)
+KMK = (MLK, PCS)
+CSJ = (PNK, JQP)
+RSN = (JRC, PSQ)
+HLL = (KVJ, QTX)
+KXM = (RJC, BKQ)
+KCR = (MSM, SPN)
+BFA = (CMB, RSV)
+KHB = (SFH, MVS)
+PXT = (KLV, NRC)
+VSF = (XLG, XLG)
+XJK = (LRN, HXB)
+LCR = (RMJ, QLD)
+FCR = (QFF, CVG)
+DPM = (SDM, DGQ)
+TXQ = (LPK, JML)
+RLK = (DMM, KBS)
+DXQ = (KPD, RKB)
+TSV = (KGJ, HCH)
+GXQ = (SXC, MML)
+BMC = (XND, CLT)
+LBL = (TKM, HSD)
+FQS = (DSH, HML)
+MJM = (CQK, DFC)
+CJH = (XHK, XHK)
+HHM = (HJK, RKF)
+SDM = (MDD, DVL)
+NDR = (CTH, HVN)
+XVF = (PSV, KFK)
+FTV = (HFF, VXH)
+KDK = (BNK, JTB)
+AAA = (FTV, NDS)
+RDQ = (FTC, XFX)
+GSC = (BHJ, JJD)
+QBV = (BMC, JVX)
+SRJ = (RQS, BXQ)
+TRC = (JVM, QNL)
+RMR = (BSB, HBV)
+DCM = (RRF, RFJ)
+KGF = (NHF, QGX)
+PBF = (RCT, JBQ)
+XRQ = (DGP, DKR)
+CND = (DSF, VTJ)
+CCB = (SLH, HRF)
+SMS = (NDR, PTT)
+DCT = (JXQ, KQP)
+QTX = (JPH, MPK)
+MRP = (CGG, JPS)
+KQP = (BNL, VDV)
+XDR = (DRQ, FXV)
+RRL = (JVT, PGM)
+LKQ = (MTN, JRG)
+NBF = (RBB, CNK)
+CQL = (XCG, GNB)
+GLT = (JQM, KCN)
+FFN = (FLV, FVS)
+BPR = (TBJ, VCQ)
+JBN = (DXQ, DXS)
+KKN = (PQF, VGK)
+RCT = (RSB, KDK)
+MKL = (RVB, LBL)
+DDD = (BSB, HBV)
+RHX = (SQB, SHB)
+NSV = (KLF, KQG)
+MNC = (HRJ, DBS)
+QGJ = (XVL, RKD)
+KMN = (FHJ, BCF)
+VHL = (MGD, CXM)
+RVJ = (BNH, GRQ)
+QHD = (FLK, QGB)
+CQK = (MSS, FQM)
+GQT = (FXX, HVC)
+JNC = (TFD, NCS)
+SFL = (FFN, DMD)
+CTC = (CSJ, HPQ)
+TCG = (MTD, JTS)
+RTN = (QGJ, QGJ)
+VGF = (KBS, DMM)
+JNL = (RGC, CLB)
+THG = (GSV, VSJ)
+VDV = (HCL, FLT)
+QGB = (DRN, CBG)
+VPP = (RTD, GQT)
+DHF = (FQS, GNH)
+PTR = (KJN, XRG)
+DQF = (CTN, GXQ)
+VLN = (GNF, TKV)
+JBC = (SFL, CVK)
+LQR = (JML, LPK)
+JPH = (THG, SVP)
+CVP = (JFM, VLN)
+VXT = (HMF, FFR)
+HHK = (QGJ, SSZ)
+MLK = (LVD, KPB)
+QJF = (QVC, FBM)
+KTS = (XRC, MQS)
+HSM = (SGR, BKG)
+DBN = (TKB, XJK)
+QRF = (HHX, TSH)
+FMJ = (CPK, JHL)
+HLK = (PJV, SBH)
+FNB = (MCV, NHG)
+HPQ = (JQP, PNK)
+RDN = (QXH, VGC)
+SHB = (KXM, TFJ)
+MDD = (QGD, VRM)
+NTP = (QMB, XLV)
+MKH = (VCX, FRC)
+DGK = (LCH, MGJ)
+TKV = (VFH, DXK)
+NHX = (GPH, KRT)
+GVC = (MGQ, JNH)
+MQS = (VXT, KSH)
+XFM = (SMX, PTR)
+KCH = (KVR, PXF)
+RKB = (HMV, DLD)
+PTN = (TVJ, PXC)
+LQP = (PKV, DBJ)
+MGJ = (JTG, SMG)
+FNS = (QLD, RMJ)
+KVR = (VNF, CDH)
+RXV = (XSF, XXL)
+TFJ = (BKQ, RJC)
+KNK = (JBN, VTC)
+QKK = (CHR, XCP)
+HXB = (VBD, HLP)
+KGL = (PCX, JSQ)
+KSR = (CMH, JLT)
+PJT = (DRQ, FXV)
+DSS = (SKK, XQQ)
+VXH = (CVR, TMC)
+RGJ = (TKT, CTC)
+FVK = (SFQ, TVD)
+BKD = (QTX, KVJ)
+HHX = (DVD, GTG)
+NFH = (PLM, PDC)
+DBS = (KJM, RVG)
+QFN = (CMX, JSR)
+GVK = (CMH, JLT)
+VGJ = (SCV, TDB)
+VVD = (HBX, GTC)
+HNX = (PLF, RBG)
+HFF = (CVR, TMC)
+JSR = (DFV, FDT)
+HMH = (CFN, FCT)
+XFF = (HHM, DRV)
+CML = (RVJ, VPD)
+HFL = (HVB, GML)
+HST = (RMG, FRK)
+JVX = (XND, CLT)
+DMD = (FVS, FLV)
+XLV = (VHL, NBP)
+HJK = (QHD, GHG)
+HCH = (MVN, VKK)
+JTF = (HVB, GML)
+PLM = (BMM, DST)
+FKD = (FBL, KNK)
+FVS = (HSM, TVT)
+GNH = (DSH, HML)
+CBL = (GLQ, XBC)
+KBK = (QJG, GGJ)
+PXF = (CDH, VNF)
+VRM = (NPL, CVT)
+LKR = (XCG, XCG)
+VXV = (DVN, KHM)
+VNF = (HST, RMC)
+FKG = (XFG, LCQ)
+QGX = (RXJ, LXN)
+PNL = (PDC, PLM)
+DVL = (VRM, QGD)
+SQB = (TFJ, KXM)
+PCX = (TTS, MKL)
+FDT = (SJT, KQN)
+QTS = (CRQ, DKM)
+MJG = (CVK, SFL)
+BXP = (HGM, QJF)
+MCK = (NJM, MMP)
+KLV = (PJT, XDR)
+RKD = (JNB, KTS)
+FLT = (FCR, RHH)
+QGS = (DPM, PHJ)
+LVB = (RSF, HJV)
+XCH = (XBX, XFM)
+FTG = (DPM, PHJ)
+RGC = (SNM, LJJ)
+QCC = (NRD, HNK)
+LJM = (SRJ, CCP)
+SFQ = (PJL, FMJ)
+NRX = (MVP, RSP)
+PKC = (XFD, NMR)
+SPB = (JTF, HFL)
+BVM = (MCS, FVK)
+DRQ = (LKR, CQL)
+PCS = (KPB, LVD)
+HLP = (GPP, PND)
+HVN = (KHB, TBT)
+SCD = (GQH, NKP)
+NPB = (PJV, SBH)
+XQQ = (CJP, JLG)
+CHX = (KSJ, GJD)
+RGQ = (GLV, GLV)
+DCS = (KHQ, DTB)
+MCV = (SFK, CFM)
+SCS = (RXV, MGV)
+TKM = (XFF, TMV)
+BSD = (GTB, VPC)
+RPC = (SRJ, CCP)
+TLN = (JFM, VLN)
+MTN = (GFP, JFP)
+FVP = (HGP, XNS)
+JQX = (TQH, KGL)
+LQG = (CSV, DFR)
+SKK = (JLG, CJP)
+MVN = (MJG, JBC)
+RKT = (GLT, QRM)
+STV = (FBL, KNK)
+MQC = (BBS, XGG)
+FFR = (LJL, DQP)
+BDF = (MSM, SPN)
+FQM = (TCG, CQC)
+HNK = (NRF, CPT)
+VKL = (DCM, DTS)
+GDF = (JQX, PJX)
+FBL = (VTC, JBN)
+JDP = (XNG, QFL)
+NLX = (CLM, DGK)
+NRD = (CPT, NRF)
+HKH = (FNS, LCR)
+TRR = (DTM, DTM)
+SGR = (LSS, BJX)
+DSN = (DDB, TQZ)
+KPB = (FXT, PBF)
+DQP = (PGF, DCT)
+SMX = (KJN, XRG)
+GDG = (VPP, PXQ)
+KKT = (CSV, DFR)
+GPP = (NLX, LHJ)
+DTS = (RRF, RFJ)
+HXV = (JVX, BMC)
+JCB = (VDK, QLF)
+PRR = (FQH, DSN)
+TFD = (RTV, TGX)
+DMM = (FKD, STV)
+KMV = (PPH, RSJ)
+HGP = (QMM, DCC)
+NCS = (RTV, TGX)
+VCQ = (XPG, XHV)
+QSD = (RFX, XHH)
+SPN = (HND, DJN)
+DBR = (CSD, LFG)
+DST = (GDG, KKR)
+BGV = (NRD, HNK)
+KQN = (DDD, RMR)
+CNP = (HGM, QJF)
+MFR = (DHV, NSV)
+VSJ = (JJJ, RFR)
+CXF = (CXQ, SRV)
+SCF = (CTN, GXQ)
+HVB = (CML, SQT)
+QHN = (MVP, RSP)
+HGM = (FBM, QVC)
+XGG = (MTL, BNZ)
+JMT = (DKH, PNP)
+MVK = (KRT, GPH)
+BTC = (PNH, PRJ)
+MLL = (TRR, RVQ)
+VPD = (GRQ, BNH)
+XBC = (FSC, KGX)
+SFK = (HCK, CCB)
+PNK = (QFN, VHD)
+SQT = (VPD, RVJ)
+QXH = (KCR, BDF)
+JQM = (CVH, XCH)
+QGD = (CVT, NPL)
+JXX = (JVM, QNL)
+RTR = (XCN, JNC)
+BMM = (GDG, KKR)
+MTF = (FVK, MCS)
+DJB = (DDN, DDN)
+GDQ = (SKK, XQQ)
+NRF = (QKK, MPP)
+CFN = (RCG, SRH)
+BSB = (LQG, KKT)
+FJX = (DSF, VTJ)
+RMJ = (VQG, CPJ)
+LFG = (VNC, RKT)
+TKT = (HPQ, CSJ)
+JRC = (BKM, BKM)
+XNG = (FTS, RDK)
+RRR = (JJD, BHJ)
+CVK = (FFN, DMD)
+TVT = (SGR, BKG)
+KSJ = (LDF, SPB)
+XSM = (JNS, MSC)
+PRJ = (SSF, HNG)
+MSG = (CSD, LFG)
+TMV = (DRV, HHM)
+BKQ = (VFP, KGF)
+SQR = (NML, HNX)
+SRH = (FNB, XRL)
+CBG = (PXT, JSM)
+MSM = (HND, DJN)
+SCV = (SML, CLH)
+QFS = (TKB, XJK)
+CLB = (LJJ, SNM)
+FRM = (QGS, FTG)
+KVX = (CQK, DFC)
+QFL = (RDK, FTS)
+DSF = (CDG, XLF)
+HML = (BMR, LDN)
+LVF = (GTB, VPC)
+XLF = (CNP, BXP)
+HMF = (DQP, LJL)
+MGZ = (RSV, CMB)
+TGX = (XRQ, XGL)
+RMC = (RMG, FRK)
+PNH = (SSF, HNG)
+PDC = (DST, BMM)
+PGF = (JXQ, KQP)
+BHJ = (DSS, GDQ)
+VNC = (QRM, GLT)
+MTL = (PQL, QRF)
+XFJ = (NRX, QHN)
+TBT = (SFH, MVS)
+HSD = (TMV, XFF)
+SSJ = (PSV, KFK)
+HXP = (GJN, RDQ)
+GRV = (GFN, CBL)
+BNL = (HCL, FLT)
+FTS = (NPB, HLK)
+PXQ = (GQT, RTD)
+RJM = (HMS, RDN)
+SPV = (JJG, TFC)
+SVP = (GSV, VSJ)
+LCL = (NJM, MMP)
+CTH = (KHB, TBT)
+JBQ = (KDK, RSB)
+XGL = (DGP, DKR)
+RRF = (QFS, DBN)
+SFF = (XHH, RFX)
+GLQ = (KGX, FSC)
+RKQ = (JNH, MGQ)
+TMF = (LQR, TXQ)
+DRN = (PXT, JSM)
+TVJ = (PLL, SQR)
+GRS = (KMV, BSM)
+FRC = (BTL, DVB)
+PLF = (FRQ, LCF)
+NMK = (FNS, LCR)
+XCN = (NCS, TFD)
+JTB = (MQN, LDX)
+CSD = (VNC, RKT)
+MGD = (HRN, LHP)
+RJG = (HXP, RQH)
+HQV = (QBV, HXV)
+NJM = (NGD, VMB)
+CBR = (GGJ, QJG)
+TMC = (LQP, KFC)
+JRH = (KVR, PXF)
+KBQ = (VDK, QLF)
+HBV = (KKT, LQG)
+RFJ = (QFS, DBN)
+CFS = (JQX, PJX)
+LNP = (QSD, SFF)
+DKM = (JQJ, FKG)
+CXR = (PKL, CHX)
+KBR = (LGJ, PTN)
+GNF = (DXK, VFH)
+DKR = (KMK, FHK)
+XQG = (CFS, GDF)
+DFA = (PNL, NFH)
+CXM = (HRN, LHP)
+XLG = (TRR, TRR)
+TTS = (RVB, LBL)
+PVS = (KVX, MJM)
+VDK = (PBX, KML)
+XHH = (FJX, CND)
+PKL = (KSJ, GJD)
+LJJ = (BVB, PRL)
+DTB = (RGP, RJG)
+HND = (MLF, MLF)
+FLK = (DRN, CBG)
+BKZ = (BLG, LVB)
+RDK = (HLK, NPB)
+MCS = (SFQ, TVD)
+HNG = (RLK, VGF)
+LGJ = (TVJ, PXC)
+LNV = (QGL, NQN)
+PKG = (XLG, MLL)
+FTC = (BKD, HLL)
+HRN = (VSF, PKG)
+MGV = (XSF, XXL)
+VTJ = (CDG, XLF)
+KSH = (FFR, HMF)
+SBH = (SPV, LVJ)
+RVG = (GBD, JDP)
+PGM = (MSG, DBR)
+JTJ = (SRV, CXQ)
+XFA = (LVB, BLG)
+BLN = (PRJ, PNH)
+QVN = (FTG, QGS)
+PRH = (FQH, FQH)
+HDD = (PRH, PRR)
+KLF = (XVF, SSJ)
+LXN = (XNL, KKN)
+QJA = (PQL, QRF)
+KVJ = (MPK, JPH)
+GRD = (CFS, GDF)
+LPK = (TKS, CXR)
+KRT = (TSV, FKN)
+XRL = (MCV, NHG)
+CGG = (RTR, VMG)
+DTM = (FTV, NDS)
+CCP = (BXQ, RQS)
+JHM = (JRG, MTN)
+RFX = (CND, FJX)
+HCL = (FCR, RHH)
+RTV = (XGL, XRQ)
+PPL = (CBL, GFN)
+ZZZ = (NDS, FTV)
+HNR = (KHM, DVN)
+NHF = (RXJ, LXN)
+JLT = (JXX, TRC)
+JNS = (HPP, KBR)
+VGC = (BDF, KCR)
+LCH = (SMG, JTG)
+LHJ = (CLM, DGK)
+NNC = (QGL, NQN)
+GSV = (RFR, JJJ)
+TDB = (SML, CLH)
+LBJ = (PRH, PRH)
+MKG = (HBX, GTC)
+VLB = (QKN, MKH)
+GQH = (QLG, RHX)
+KGQ = (SCS, XKL)
+RSJ = (GRD, XQG)
+CVT = (RRR, GSC)
+FCT = (RCG, SRH)
+XFX = (HLL, BKD)
+CPT = (QKK, MPP)
+DVN = (MCT, RRL)
+PHJ = (DGQ, SDM)
+HVC = (FRM, QVN)
+RCG = (FNB, XRL)
+FXT = (JBQ, RCT)
+JVT = (MSG, DBR)
+NGD = (XBQ, PVS)
+BMR = (MTF, BVM)
+CSV = (XFJ, KMM)
+SLH = (HKX, KMN)
+JPM = (RPC, LJM)
+QLG = (SQB, SHB)
+QVC = (JVQ, MNC)
+VGK = (RJM, BTM)
+NDQ = (QKM, KGQ)
+GCP = (RGQ, SKJ)
+DLD = (CGX, LXG)
+SFH = (NTP, VRJ)
+CVH = (XFM, XBX)
+RJC = (KGF, VFP)
+VQG = (CBR, KBK)
+CMX = (DFV, FDT)
+RHH = (CVG, QFF)
+RFR = (MKG, VVD)
+HRJ = (KJM, RVG)
+RBB = (NHX, MVK)
+JXQ = (VDV, BNL)
+PLB = (MLM, SMS)
+HMV = (CGX, LXG)
+RVB = (TKM, HSD)
+XBQ = (MJM, KVX)
+FBM = (MNC, JVQ)
+XFD = (DCS, XQN)
+TSH = (GTG, DVD)
+GHG = (QGB, FLK)
+LHP = (VSF, PKG)
+RVV = (RGJ, QJK)
+FKN = (KGJ, HCH)
+LCQ = (CJH, FNX)
+PNP = (LFK, HTB)
+MCT = (JVT, PGM)
+GFP = (XMD, QTS)
+SNM = (BVB, PRL)
+DRV = (HJK, RKF)
+VKK = (JBC, MJG)
+BTL = (PLB, PNB)
+SSZ = (RKD, XVL)
+XQN = (DTB, KHQ)
+RSV = (HQV, NNP)
+XNP = (GLJ, DBV)
+BVB = (PPL, GRV)
+QJG = (MGT, PKC)
+TSJ = (RGC, CLB)
+HPP = (LGJ, PTN)
+LVD = (FXT, PBF)
+DFR = (XFJ, KMM)
+GNB = (RTN, HHK)
+NKP = (RHX, QLG)
+CQC = (MTD, JTS)
+FRQ = (GVK, KSR)
+GLV = (LVB, BLG)
+MGT = (XFD, NMR)
+JJG = (GXJ, JSF)
+GJD = (LDF, SPB)
+DBV = (BLN, BTC)
+RXJ = (KKN, XNL)
+NRC = (PJT, XDR)
+SBA = (XVL, RKD)
+LDF = (JTF, HFL)
+KGX = (QNS, TMF)
+QFF = (RVV, QRG)
+HRF = (HKX, KMN)
+JRG = (JFP, GFP)
+SSF = (RLK, VGF)
+QMM = (HDP, PVT)
+PKV = (TLN, CVP)
+XPG = (BGV, QCC)
+JML = (CXR, TKS)
+XKL = (MGV, RXV)
+MXG = (DDN, RSN)
+GLJ = (BTC, BLN)
+NML = (RBG, PLF)
+RQS = (CXF, JTJ)
+KMM = (QHN, NRX)
+NQN = (BPR, XTJ)
+XNL = (PQF, VGK)
+JJJ = (VVD, MKG)
+CDG = (CNP, BXP)
+PBX = (TPH, XNP)
+XNS = (DCC, QMM)
+RQH = (RDQ, GJN)
+BLG = (HJV, RSF)
+BTM = (RDN, HMS)
+GRQ = (KBQ, JCB)
+JHL = (MRQ, HMH)
+DGQ = (MDD, DVL)
+GGJ = (PKC, MGT)
+QNS = (TXQ, LQR)
+XFG = (CJH, FNX)
+QMB = (VHL, NBP)
+PPH = (GRD, XQG)
+DVB = (PNB, PLB)
+NXD = (NKP, GQH)
+LDN = (BVM, MTF)
+XBX = (SMX, PTR)
+DGP = (KMK, FHK)
+JJD = (GDQ, DSS)
+CJP = (NMD, VKL)
+CVG = (QRG, RVV)
+QKM = (XKL, SCS)
+HMS = (VGC, QXH)
+CMB = (NNP, HQV)
+GTB = (LBJ, HDD)
+QKN = (VCX, FRC)
+GML = (CML, SQT)
+DVD = (DQF, SCF)
+MLM = (NDR, PTT)
+BNK = (LDX, MQN)
+MQN = (BSD, LVF)
+MPK = (THG, SVP)
+DJN = (MLF, MQC)
+SXC = (JMT, LNK)
+MVP = (SRF, GRS)
+CLM = (MGJ, LCH)
+JVM = (BQT, KTX)
+DCC = (HDP, PVT)
+JFM = (TKV, GNF)
+JSF = (JHM, LKQ)
+CDN = (QKM, KGQ)
+KQG = (XVF, SSJ)
+CLH = (LNV, NNC)
+KTX = (SCD, NXD)
+HBX = (MPG, MRP)
+JTG = (FVP, KFG)
+RSF = (LKL, KVV)
+MRQ = (FCT, CFN)
+JSM = (KLV, NRC)
+QLF = (PBX, KML)
+MTD = (KRB, JPM)
+RBG = (FRQ, LCF)
+QTG = (RKQ, GVC)
+NPL = (GSC, RRR)
+XVL = (KTS, JNB)
+PQL = (HHX, TSH)
+CDH = (RMC, HST)
+XSF = (JDV, NBF)
+RKF = (GHG, QHD)
+XMD = (DKM, CRQ)
+RVQ = (DTM, ZZZ)
+VHD = (CMX, JSR)
+RTD = (HVC, FXX)
+KFC = (PKV, DBJ)
+NHG = (CFM, SFK)
+JTS = (KRB, JPM)
+BSM = (RSJ, PPH)
+VBD = (PND, GPP)
+TKS = (PKL, CHX)
+TQZ = (NFH, PNL)
+SML = (LNV, NNC)
+HCK = (HRF, SLH)
+PXC = (SQR, PLL)
+JLG = (VKL, NMD)
+SRV = (VLB, FMR)
+PTT = (CTH, HVN)
+PLL = (HNX, NML)
+TKB = (HXB, LRN)
+CXQ = (VLB, FMR)
+NBP = (CXM, MGD)
+HDP = (NMK, HKH)
+LCF = (GVK, KSR)
+DKH = (LFK, HTB)
+LXG = (VGJ, VCP)
+QRG = (RGJ, QJK)
+KRB = (LJM, RPC)
+JDV = (RBB, CNK)
+PGX = (GNH, FQS)
+DHV = (KQG, KLF)
+QNL = (BQT, KTX)
+XCP = (HNR, VXV)
+JVQ = (HRJ, DBS)
+QLD = (CPJ, VQG)
+CLT = (BKV, NPQ)
+QRM = (JQM, KCN)
+RGP = (RQH, HXP)
+PRL = (GRV, PPL)
+KBS = (FKD, STV)
+XXL = (NBF, JDV)
+MML = (LNK, JMT)
+VFH = (JRH, KCH)
+PQF = (RJM, BTM)
+JNB = (MQS, XRC)
+VTC = (DXQ, DXS)
+XCG = (RTN, RTN)
+MGQ = (LNP, VNP)
+BXQ = (CXF, JTJ)
+JNH = (LNP, VNP)
+BKM = (CMB, RSV)
+PJX = (KGL, TQH)
+SMG = (FVP, KFG)
+LRN = (HLP, VBD)
+XRC = (KSH, VXT)
+MPG = (JPS, CGG)
+XHV = (QCC, BGV)
+KHM = (RRL, MCT)
+RSB = (BNK, JTB)
+PNB = (MLM, SMS)
+XHK = (RGQ, RGQ)
+NNP = (HXV, QBV)
+GTC = (MPG, MRP)
+LNK = (PNP, DKH)
+FHJ = (TCF, MFR)
+HJV = (KVV, LKL)
+GFN = (XBC, GLQ)
+JQP = (VHD, QFN)
+CPJ = (CBR, KBK)
+NMD = (DCM, DTS)
+KML = (TPH, XNP)
+CHR = (HNR, VXV)
+JSQ = (MKL, TTS)
+FQH = (DDB, DDB)
+CNK = (MVK, NHX)
+VCX = (BTL, DVB)
+KHQ = (RGP, RJG)
+BKG = (LSS, BJX)
+KKR = (PXQ, VPP)
+LKL = (DHF, PGX)
+PJV = (SPV, LVJ)
+SKJ = (GLV, BKZ)
+TCF = (DHV, NSV)
+DXK = (JRH, KCH)
+DFV = (KQN, SJT)
+KJN = (DJB, MXG)
+BKV = (TSJ, JNL)
+JQJ = (XFG, LCQ)
+HTB = (XSM, SHM)
+NPQ = (TSJ, JNL)
+FXV = (LKR, CQL)
+NDS = (HFF, VXH)
+KFK = (BPN, QTG)
+GTG = (DQF, SCF)
+FSC = (QNS, TMF)
diff --git a/2023/08-Haunted_Wasteland/second.hs b/2023/08-Haunted_Wasteland/second.hs
new file mode 100644
index 0000000..656367a
--- /dev/null
+++ b/2023/08-Haunted_Wasteland/second.hs
@@ -0,0 +1,76 @@
+-- requires cabal install --lib megaparsec parser-combinators
+module Main (main) where
+
+import Control.Applicative.Permutations
+import Control.Monad (void, when)
+import Data.Char qualified as C
+import Data.Either
+import Data.Functor
+import Data.List qualified as L
+import Data.Map qualified as M
+import Data.Maybe
+import Data.Set qualified as S
+import Data.Void (Void)
+import Text.Megaparsec
+import Text.Megaparsec.Char
+
+import Debug.Trace
+
+exampleExpectedOutput = 6
+
+data Direction = L | R deriving (Eq, Show)
+type Branch = (String, String)
+type Map = M.Map String Branch
+data Input = Input [Direction] Map deriving Show
+
+type Parser = Parsec Void String
+
+parseDirection :: Parser Direction
+parseDirection = char 'L' $> L
+             <|> char 'R' $> R
+
+parseNode :: Parser String
+parseNode = some alphaNumChar
+
+parseBranch :: Parser Branch
+parseBranch = (,) <$> (char '(' *> parseNode)
+                  <*> (string ", " *> parseNode <* char ')')
+
+parseMapElt :: Parser (String, Branch)
+parseMapElt = (,) <$> (parseNode <* string " = ")
+                  <*> (parseBranch <* eol)
+
+parseInput' :: Parser Input
+parseInput' = Input <$> some parseDirection <* eol <* eol
+                    <*> (M.fromList <$> some parseMapElt <* eof)
+
+parseInput :: String -> IO Input
+parseInput filename = do
+  input <- readFile filename
+  case runParser parseInput' filename input of
+    Left bundle -> error $ errorBundlePretty bundle
+    Right input' -> return input'
+
+compute :: Input -> Int
+compute (Input directions m) = L.foldr (lcm . pathLength 0) 1 startingNodes
+  where
+    startingNodes = L.filter ((==) 'A' . last) $ M.keys m
+    pathLength :: Int -> String -> Int
+    pathLength i node | last node == 'Z' = i
+                      | otherwise = pathLength (i+1) (nextOne node)
+      where
+        nextOne :: String -> String
+        nextOne = next . (m M.!)
+        next :: Branch -> String
+        next | directions L.!! (i `mod` l) == L = fst
+             | otherwise = snd
+    l = length directions
+
+main :: IO ()
+main = do
+  example <- parseInput "example2"
+  let exampleOutput = compute example
+  when  (exampleOutput /= exampleExpectedOutput)  (error $ "example failed: got " ++ show exampleOutput ++ " instead of " ++ show exampleExpectedOutput)
+  input <- parseInput "input"
+  print $ compute input
+