From f83dea0c8f380e760f4d124d48ea9062838bf14a Mon Sep 17 00:00:00 2001
From: Shadowfacts <me@shadowfacts.net>
Date: Fri, 8 Dec 2023 12:22:54 -0500
Subject: [PATCH] Day 8

---
 input/day8.txt | 704 +++++++++++++++++++++++++++++++++++++++++++++++++
 src/day08.rs   | 166 ++++++++++++
 src/main.rs    |   3 +-
 3 files changed, 872 insertions(+), 1 deletion(-)
 create mode 100644 input/day8.txt
 create mode 100644 src/day08.rs

diff --git a/input/day8.txt b/input/day8.txt
new file mode 100644
index 0000000..638c2f4
--- /dev/null
+++ b/input/day8.txt
@@ -0,0 +1,704 @@
+LRRLRLRRLRRRLRLRLRRLRRRLRRRLRRLRRRLRLRLRLRLRLRLRRRLRRLRRRLLLLRRRLRLLLRRRLLRLLRRRLRRRLRLRRLRRRLRRRLLRRRLRLRRRLLRRRLRLLRRRLRRLLRLRLRLRRRLRLLRLRLRRRLRLLRLRLRRRLLRRRLRRLRRRLRLRRLRLRRLRLRRLRRRLLRRRLLLRRRLLRRLRRLRRLRLLRRLRRRLRRLRLRLRRLRRLLLRRLRLRRRLRRRLRRRLLLRLRRRLLRRRLRLLRRRR
+
+NFK = (LMH, RSS)
+SLJ = (NBT, CDG)
+SKX = (SRC, KKX)
+LRB = (MNG, FSH)
+QMQ = (DMG, QRV)
+VRB = (PGG, PRG)
+QNB = (PFD, FFQ)
+BPK = (GFF, DFF)
+JTD = (NVV, VLD)
+PXD = (VNV, BDS)
+PXP = (VFH, DLR)
+XRH = (QMM, LDH)
+GLV = (SDM, MFS)
+TTM = (VGH, SJG)
+RHC = (DBR, QSQ)
+KNP = (FFB, SSB)
+VLL = (VNM, XQQ)
+SMJ = (PNH, MML)
+XJN = (SCD, TPG)
+GJL = (RJK, GGH)
+NFD = (CKB, HXV)
+XPH = (CDT, CVK)
+GNJ = (JFV, KLQ)
+CKC = (PCP, RXV)
+PTN = (MFX, GXV)
+HSD = (MGC, CGB)
+MFX = (MCK, PKT)
+QVQ = (LDG, JNX)
+PBB = (DXK, KJL)
+VNG = (JCH, GPT)
+LFM = (HCK, GGQ)
+SGL = (QPC, FJF)
+RFK = (VMS, CRB)
+TTJ = (RMQ, XHJ)
+FJP = (GCL, KXF)
+BRS = (LRK, NFD)
+HTL = (CBJ, BFM)
+QFP = (LRG, XQF)
+KKH = (QSQ, DBR)
+SLA = (HLN, TMV)
+JGS = (VMH, CHF)
+VNS = (HLN, TMV)
+FFM = (KKX, SRC)
+JHJ = (FMR, LVD)
+QSQ = (JVR, VVX)
+QKN = (LFQ, MDJ)
+JDC = (XFF, GFS)
+RPC = (TFS, TQL)
+HGD = (BHN, HKH)
+NDB = (CMJ, KDK)
+CQP = (TCK, RFK)
+SSB = (SNS, XPX)
+VXB = (QRS, SHF)
+RRT = (PJX, LTG)
+BBQ = (SBX, CFK)
+DJD = (KMQ, CHQ)
+LXR = (VXS, FLP)
+VHD = (QVQ, LQQ)
+BFM = (VQS, VMX)
+QGL = (CBD, VHD)
+MML = (SLT, MCH)
+VGV = (SNX, QBN)
+KND = (SQS, JFC)
+NFX = (XVF, GLX)
+HCK = (DFX, JGS)
+RSS = (MGG, CNL)
+KRH = (RKF, KJR)
+GMV = (BLX, FKF)
+CFB = (XPC, RRF)
+KLQ = (JGV, SNL)
+KCR = (NTC, GQL)
+SCB = (JSG, VBB)
+TSJ = (VSJ, HQD)
+SNL = (NNP, XBN)
+RXV = (PMB, RRT)
+MTH = (PCC, BPK)
+RRD = (GNL, MSJ)
+NVT = (CMD, FCF)
+KNF = (SQQ, JPS)
+SMK = (CKC, QTJ)
+RFB = (FDN, CJB)
+QXD = (NRN, GLV)
+LCR = (TRT, NMR)
+DPR = (GRM, HLQ)
+CMD = (FMV, NGL)
+LHP = (VVP, LCR)
+NDN = (BRH, PTF)
+JFC = (HFV, DLQ)
+VMX = (NVL, KVQ)
+HJF = (QFD, NDN)
+XHC = (JVC, JKS)
+LBN = (CCG, JRV)
+LPK = (XCM, VXL)
+HXJ = (TTM, PPT)
+GNL = (HNK, QQJ)
+VRK = (MRC, XPH)
+DJF = (CLD, NGD)
+KVP = (DJD, FXM)
+JHQ = (VNS, RPZ)
+FSK = (XCM, VXL)
+HCJ = (PJB, PBF)
+FJC = (TTJ, XHB)
+JVR = (VRH, RBM)
+NVL = (CQD, PJL)
+QNL = (GXD, DHK)
+NHK = (RFB, MXR)
+VQP = (BBG, PXD)
+SPV = (LMN, DTT)
+KJR = (PFJ, HPH)
+VGH = (PGC, NGH)
+SQQ = (DQV, BLM)
+DTQ = (SMB, CNC)
+RVB = (JRQ, JRQ)
+KKF = (SGL, NNN)
+MTP = (MHN, JGN)
+PNX = (PMS, XHV)
+CTR = (XBB, VRB)
+DFX = (CHF, VMH)
+QQM = (SRG, PSR)
+GLQ = (FHJ, TQD)
+RLJ = (LNR, NRS)
+JLJ = (DRR, MCV)
+PRJ = (XHF, SMK)
+XKQ = (HCJ, SHG)
+HJL = (BBG, PXD)
+MGC = (RLV, DPR)
+GLX = (RHC, KKH)
+AAA = (QRH, FRS)
+LSB = (XXB, XKQ)
+VNQ = (NVC, XTP)
+FJR = (HGD, SBH)
+MHX = (LRH, QGL)
+LMN = (STQ, STQ)
+FPT = (HQH, QQM)
+VGB = (MRC, XPH)
+VKB = (JXN, SKV)
+VHJ = (PRT, DTQ)
+QPC = (JLJ, XXR)
+CJJ = (KXB, VXB)
+SHG = (PBF, PJB)
+SKV = (RHQ, VCC)
+FMH = (LTT, HNX)
+SKQ = (SKX, FFM)
+LRG = (VHN, VHN)
+GCL = (RBQ, MKB)
+XVJ = (PQQ, FNC)
+HPV = (XHF, SMK)
+MCX = (GDX, JMV)
+NNN = (QPC, FJF)
+HNK = (CPS, NHK)
+VBB = (FDV, FMJ)
+TCD = (BFM, CBJ)
+TBV = (BSL, FKK)
+CPT = (LTT, HNX)
+CDL = (DCL, SMS)
+JGN = (SHK, KTG)
+CRB = (PXP, PPH)
+JPS = (DQV, BLM)
+MMS = (HJF, MGK)
+JFT = (FFQ, PFD)
+PGC = (TQP, BDN)
+RPZ = (TMV, HLN)
+FVD = (GTM, PDN)
+RTB = (FTM, QBK)
+DML = (XKK, LMP)
+QGH = (MHX, PXH)
+RHM = (TFS, TQL)
+GXB = (LXM, NPC)
+CMJ = (LXR, PHP)
+FFB = (SNS, XPX)
+MKC = (QMM, LDH)
+MCK = (TRP, VXJ)
+FNL = (QNB, JFT)
+GGQ = (JGS, DFX)
+NMR = (MQP, TNX)
+XKK = (XLK, VKB)
+QML = (LBN, FRH)
+JCH = (GQH, CLR)
+TMV = (BMV, TKL)
+FDN = (HCM, VVS)
+GPT = (CLR, GQH)
+DDC = (QGH, KVN)
+DKK = (LBN, FRH)
+RBM = (SLJ, NLJ)
+KLB = (LFV, SPT)
+GRK = (XNP, VLL)
+CLD = (CSS, GXT)
+GFS = (KRH, TRK)
+RQJ = (RQX, SQM)
+KTG = (NCX, NGJ)
+HNX = (JQB, SBJ)
+NTR = (VRB, XBB)
+HMF = (BGH, QKN)
+TPB = (LMN, DTT)
+GHX = (QBK, FTM)
+RMT = (RFK, TCK)
+MSR = (NMQ, LJC)
+PPT = (SJG, VGH)
+QMG = (VRG, SFZ)
+FKF = (LHJ, QHG)
+QRL = (LRD, RHJ)
+TFS = (GRK, JTQ)
+FMJ = (TSF, SXS)
+SBX = (GGT, VCL)
+KFG = (FCX, FTF)
+VXS = (RBG, KNP)
+VDG = (JDT, RPS)
+QHD = (RFN, ZZZ)
+SFM = (GLL, RQC)
+VXL = (DCK, FMG)
+CCD = (LMP, XKK)
+SJG = (PGC, NGH)
+FKK = (BPP, HSD)
+TXG = (FDC, JNJ)
+RKF = (PFJ, HPH)
+PMS = (HMT, XTG)
+MHN = (SHK, KTG)
+DXK = (FPT, JSJ)
+QCQ = (LRM, MCX)
+QPR = (MST, QHD)
+CKV = (VNS, VNS)
+DRJ = (VLD, NVV)
+FGT = (RHM, RPC)
+LHJ = (BQK, JHJ)
+STQ = (CKV, CKV)
+HLQ = (FXR, KKJ)
+GBQ = (BHT, HJH)
+RNH = (KNF, GGX)
+VPG = (PRR, FHK)
+CTS = (VVP, LCR)
+CPS = (MXR, RFB)
+DRR = (NFK, TKJ)
+MQG = (HJH, BHT)
+RTL = (GBQ, MQG)
+KSV = (HGD, SBH)
+TKJ = (LMH, RSS)
+FHF = (VCB, BKJ)
+CSL = (JNS, FTP)
+NMQ = (XPL, PBB)
+CNL = (VJJ, JBV)
+QQF = (GRF, DKC)
+PJB = (PPD, TBV)
+BDN = (HBD, RRD)
+VRG = (QDM, DVP)
+MGK = (NDN, QFD)
+CCG = (BQR, QBM)
+MQP = (CLF, HNQ)
+TPG = (VPG, BMF)
+VPP = (QBN, SNX)
+FXM = (KMQ, CHQ)
+CDG = (PPP, KFN)
+LVA = (QDM, DVP)
+QMM = (RFF, LNJ)
+LMP = (VKB, XLK)
+MHH = (HBN, FJC)
+JBC = (LTN, LTN)
+MGG = (VJJ, JBV)
+MPF = (LXM, NPC)
+JGV = (XBN, NNP)
+MNK = (VGL, DJB)
+FGX = (BVQ, DQK)
+XBJ = (RQC, GLL)
+KGB = (MCX, LRM)
+HXX = (MHH, TXD)
+XLK = (SKV, JXN)
+FCJ = (VPT, GQC)
+SHK = (NCX, NGJ)
+QRH = (BTG, FJP)
+LXM = (KGB, QCQ)
+DXV = (SLM, SCK)
+MRC = (CVK, CDT)
+QBN = (PKR, KQM)
+PPD = (FKK, BSL)
+PXH = (QGL, LRH)
+XXB = (SHG, HCJ)
+DCK = (DSL, DSL)
+PMG = (TXD, MHH)
+XKG = (TQD, FHJ)
+JRV = (QBM, BQR)
+VGL = (TGD, XTD)
+XCM = (DCK, FMG)
+PQN = (RPS, JDT)
+JBV = (NTR, CTR)
+TXD = (HBN, FJC)
+VJJ = (CTR, NTR)
+DCL = (SMJ, GXC)
+PCP = (RRT, PMB)
+LRD = (XHC, PBG)
+QTJ = (PCP, RXV)
+VMH = (PKK, RTL)
+DBP = (PRJ, HPV)
+CLR = (VDG, PQN)
+FLP = (KNP, RBG)
+RJT = (NDB, PTK)
+KFN = (CDL, FDM)
+DKC = (CJJ, HTB)
+XHV = (XTG, HMT)
+CFK = (GGT, VCL)
+HGX = (RDT, GKM)
+CKB = (CQP, RMT)
+KVQ = (CQD, PJL)
+PSR = (HGX, JLK)
+KTC = (JFV, KLQ)
+RMN = (SFM, XBJ)
+KMQ = (JDC, MRB)
+TXB = (FSR, MQD)
+BKS = (FLH, QFP)
+PFD = (MNK, BKL)
+BQR = (LGC, KKF)
+NPA = (FCJ, NPF)
+FRR = (MMS, TDR)
+BSL = (HSD, BPP)
+LMH = (MGG, CNL)
+TVH = (TBH, DKP)
+GXT = (JTD, DRJ)
+DFF = (TFC, KNN)
+RPS = (DBP, LXB)
+HKH = (VNQ, DPG)
+NRS = (VGR, DPS)
+FKT = (NDB, PTK)
+GGX = (SQQ, JPS)
+GDA = (LGN, DDC)
+RBG = (FFB, SSB)
+HBN = (TTJ, XHB)
+BLM = (TXG, JVD)
+VRH = (NLJ, SLJ)
+XPL = (DXK, KJL)
+VNM = (XXJ, QNL)
+MDC = (MTP, TGC)
+GQL = (KSN, VKN)
+TNX = (HNQ, CLF)
+NVV = (HVF, FGX)
+DXM = (PTN, QGM)
+XBB = (PRG, PGG)
+RLM = (XKQ, XXB)
+TGC = (JGN, MHN)
+SDM = (SLV, KVS)
+BPP = (MGC, CGB)
+QVB = (QFM, QMG)
+LJC = (PBB, XPL)
+QLG = (PPT, TTM)
+XTT = (BGH, QKN)
+HTB = (VXB, KXB)
+VCC = (MKC, XRH)
+LRM = (GDX, JMV)
+CJB = (HCM, VVS)
+TRK = (KJR, RKF)
+TFC = (CHT, LBT)
+NVC = (TCD, HTL)
+JRQ = (LGN, DDC)
+SQS = (DLQ, HFV)
+CHF = (PKK, RTL)
+PGG = (RQJ, PJM)
+PRR = (JGP, MSR)
+VHN = (QFM, QFM)
+RQC = (GNJ, KTC)
+MRB = (GFS, XFF)
+XBN = (XJN, DXC)
+SXS = (BBQ, XFV)
+VCB = (LPK, FSK)
+FTM = (SPV, TPB)
+PJL = (SPJ, VHJ)
+BKL = (DJB, VGL)
+GRR = (DJD, FXM)
+ZZZ = (FRS, QRH)
+KDK = (PHP, LXR)
+SNX = (KQM, PKR)
+VMS = (PXP, PPH)
+FSH = (RJT, FKT)
+JDT = (DBP, LXB)
+KVN = (PXH, MHX)
+DHK = (DLT, PNX)
+JSG = (FDV, FMJ)
+GQT = (NRN, GLV)
+NBT = (PPP, KFN)
+PMX = (KVT, RMN)
+SBH = (HKH, BHN)
+MNG = (FKT, RJT)
+FNC = (JSV, HKZ)
+KXF = (MKB, RBQ)
+DTT = (STQ, VFM)
+PKT = (VXJ, TRP)
+XXR = (DRR, MCV)
+VKN = (GRR, KVP)
+FJF = (XXR, JLJ)
+SMB = (RTB, GHX)
+RHJ = (PBG, XHC)
+CDR = (RJK, GGH)
+RBQ = (PMG, HXX)
+XCT = (NTC, GQL)
+FMR = (JLQ, QRL)
+SNS = (XKG, GLQ)
+FSR = (NCR, LRB)
+PKK = (GBQ, MQG)
+VXJ = (FDS, TSJ)
+QTQ = (BLX, FKF)
+KSN = (GRR, KVP)
+FCX = (RLJ, TQN)
+VNV = (VQV, MTH)
+HVF = (BVQ, DQK)
+CHQ = (JDC, MRB)
+MKB = (HXX, PMG)
+FRH = (JRV, CCG)
+CQC = (QML, DKK)
+SPJ = (DTQ, PRT)
+HXV = (CQP, RMT)
+CBJ = (VMX, VQS)
+FHG = (FSR, MQD)
+GFF = (KNN, TFC)
+XVF = (RHC, KKH)
+QRS = (RNL, FGT)
+XFV = (CFK, SBX)
+HPH = (SXL, CXD)
+FHK = (JGP, MSR)
+HQH = (SRG, PSR)
+LTT = (SBJ, JQB)
+GGT = (NFB, GSS)
+PRM = (VRR, MDC)
+HMT = (CPT, FMH)
+DSL = (MST, MST)
+TDM = (QML, DKK)
+LHX = (FRR, GSC)
+LHG = (DKC, GRF)
+PNH = (MCH, SLT)
+VFH = (HMF, XTT)
+VCL = (GSS, NFB)
+PPH = (VFH, DLR)
+FHJ = (DML, CCD)
+LFQ = (LSB, RLM)
+RFV = (LRK, NFD)
+JSV = (FCJ, NPF)
+DVP = (GDC, RNH)
+SXL = (VQP, HJL)
+NPC = (QCQ, KGB)
+JVC = (FGQ, GGJ)
+RQX = (TFQ, BCL)
+TFQ = (TPT, KLB)
+NPL = (DXN, CMZ)
+GKM = (MPQ, BTX)
+HSS = (KVT, RMN)
+JDF = (HXJ, QLG)
+XFF = (TRK, KRH)
+DBR = (JVR, VVX)
+PJM = (SQM, RQX)
+MRF = (JFC, SQS)
+BQK = (FMR, LVD)
+PHP = (VXS, FLP)
+LTN = (DXN, DXN)
+PPP = (CDL, FDM)
+TBH = (SCB, VCK)
+CGB = (RLV, DPR)
+TDR = (HJF, MGK)
+LFV = (PVB, FHF)
+NDL = (FLH, QFP)
+KHR = (RVB, RVB)
+GRM = (FXR, KKJ)
+RFF = (FNL, HMG)
+JLK = (GKM, RDT)
+TQD = (CCD, DML)
+FDV = (SXS, TSF)
+XTP = (TCD, HTL)
+PCC = (GFF, DFF)
+LDG = (QQF, LHG)
+HLN = (TKL, BMV)
+DPG = (XTP, NVC)
+MNH = (GLX, XVF)
+SCD = (BMF, VPG)
+GSS = (MNH, NFX)
+NXR = (MRF, KND)
+PVB = (VCB, BKJ)
+XHF = (QTJ, CKC)
+NRN = (MFS, SDM)
+RLV = (HLQ, GRM)
+DLF = (CMD, FCF)
+VQV = (BPK, PCC)
+BHT = (GBF, DRL)
+HQD = (NVT, DLF)
+CHT = (SLH, JGK)
+NFF = (VRR, MDC)
+KVT = (XBJ, SFM)
+DLQ = (LHX, XRD)
+NCR = (FSH, MNG)
+VDD = (PQQ, PQQ)
+JVD = (FDC, JNJ)
+VQS = (KVQ, NVL)
+NGJ = (XJT, CTJ)
+BGT = (RRF, XPC)
+QDD = (RVB, BCF)
+DPS = (CDR, GJL)
+JFV = (JGV, SNL)
+SLM = (QTQ, GMV)
+SBS = (TDM, CQC)
+BHN = (DPG, VNQ)
+FLH = (LRG, XQF)
+SBJ = (LTB, SKQ)
+FXR = (LFM, BGQ)
+NGH = (TQP, BDN)
+KQM = (SBS, RSQ)
+KPB = (SLM, SCK)
+HCM = (VFF, DJF)
+LXB = (HPV, PRJ)
+STZ = (DDC, LGN)
+HMG = (QNB, JFT)
+FMG = (DSL, QPR)
+XPX = (XKG, GLQ)
+CBD = (QVQ, LQQ)
+LRH = (VHD, CBD)
+SMS = (SMJ, GXC)
+QQJ = (NHK, CPS)
+XQQ = (QNL, XXJ)
+LTB = (FFM, SKX)
+JLQ = (RHJ, LRD)
+TQP = (HBD, RRD)
+RFN = (QRH, FRS)
+HJH = (GBF, DRL)
+RNL = (RHM, RPC)
+LVD = (JLQ, QRL)
+TQL = (JTQ, GRK)
+MPQ = (NFF, PRM)
+BKJ = (FSK, LPK)
+FTF = (TQN, RLJ)
+LDH = (LNJ, RFF)
+VFF = (CLD, NGD)
+TQN = (LNR, NRS)
+GXV = (MCK, PKT)
+DXN = (KPB, DXV)
+TCK = (CRB, VMS)
+HNQ = (VNG, DHL)
+JNS = (KHR, KHR)
+BBG = (BDS, VNV)
+JXN = (RHQ, VCC)
+RCA = (KPB, DXV)
+BGQ = (HCK, GGQ)
+BCF = (JRQ, STZ)
+GDC = (GGX, KNF)
+DXC = (TPG, SCD)
+DLR = (XTT, HMF)
+PTK = (CMJ, KDK)
+SKP = (TXB, FHG)
+PFJ = (CXD, SXL)
+KVS = (CFB, BGT)
+PRT = (SMB, CNC)
+MCV = (TKJ, NFK)
+FGQ = (GXB, MPF)
+SLH = (FJR, KSV)
+MQD = (LRB, NCR)
+VRR = (TGC, MTP)
+TPT = (SPT, LFV)
+DTK = (HXJ, QLG)
+CVK = (QSM, TVH)
+RRF = (KKN, KFG)
+FCF = (FMV, NGL)
+DJB = (TGD, XTD)
+FTP = (KHR, QDD)
+CSS = (DRJ, JTD)
+QGM = (MFX, GXV)
+CXD = (HJL, VQP)
+TRP = (FDS, TSJ)
+PQQ = (JSV, JSV)
+RHQ = (MKC, XRH)
+FFQ = (BKL, MNK)
+JGP = (NMQ, LJC)
+LGC = (SGL, NNN)
+LQQ = (LDG, JNX)
+SBV = (JNS, FTP)
+XHB = (RMQ, XHJ)
+CQD = (VHJ, SPJ)
+RDT = (MPQ, BTX)
+LHL = (LTN, NPL)
+LRK = (CKB, HXV)
+MCH = (HSS, PMX)
+QFD = (BRH, PTF)
+PKR = (RSQ, SBS)
+JNX = (LHG, QQF)
+KLX = (PTN, QGM)
+MDJ = (LSB, RLM)
+TGD = (NXR, DGD)
+MST = (RFN, RFN)
+BCL = (KLB, TPT)
+VPT = (VRK, VGB)
+JMV = (DTK, JDF)
+PJX = (NDL, BKS)
+GGJ = (GXB, MPF)
+NNP = (XJN, DXC)
+PMB = (PJX, LTG)
+QFM = (VRG, VRG)
+BTX = (PRM, NFF)
+DKP = (SCB, VCK)
+BMF = (FHK, PRR)
+JTQ = (VLL, XNP)
+SRG = (JLK, HGX)
+RMQ = (RFV, BRS)
+JGK = (FJR, KSV)
+KNN = (CHT, LBT)
+JQB = (SKQ, LTB)
+DHL = (GPT, JCH)
+NTC = (KSN, VKN)
+QRV = (LHP, CTS)
+VFM = (CKV, JHQ)
+LBT = (SLH, JGK)
+GXC = (PNH, MML)
+HFV = (LHX, XRD)
+TRT = (TNX, MQP)
+FDM = (DCL, SMS)
+KXB = (SHF, QRS)
+VSJ = (NVT, DLF)
+KJL = (JSJ, FPT)
+LTG = (BKS, NDL)
+SQM = (TFQ, BCL)
+PTF = (KCP, QMQ)
+LGN = (KVN, QGH)
+PBG = (JKS, JVC)
+DQK = (XFG, XCP)
+XFG = (MXD, FVD)
+PRG = (RQJ, PJM)
+FRS = (BTG, FJP)
+XNP = (VNM, XQQ)
+XRD = (GSC, FRR)
+RSQ = (TDM, CQC)
+MFS = (KVS, SLV)
+SPT = (PVB, FHF)
+DRL = (VPP, VGV)
+VVP = (NMR, TRT)
+XTG = (CPT, FMH)
+SCK = (GMV, QTQ)
+VCK = (VBB, JSG)
+DQV = (TXG, JVD)
+XPC = (KKN, KFG)
+KXJ = (FHG, TXB)
+MSJ = (QQJ, HNK)
+VGR = (GJL, CDR)
+QDM = (RNH, GDC)
+NGD = (GXT, CSS)
+FDS = (HQD, VSJ)
+NFB = (NFX, MNH)
+CNC = (GHX, RTB)
+BDS = (VQV, MTH)
+DGD = (KND, MRF)
+CTJ = (VDD, XVJ)
+JSJ = (QQM, HQH)
+GXD = (PNX, DLT)
+TSF = (XFV, BBQ)
+GLL = (GNJ, KTC)
+CMZ = (DXV, KPB)
+SRC = (QXD, GQT)
+FMV = (JBC, JBC)
+NPF = (GQC, VPT)
+HBD = (GNL, MSJ)
+CDT = (TVH, QSM)
+JNJ = (SKP, KXJ)
+NGL = (JBC, LHL)
+SFZ = (DVP, QDM)
+GTM = (DXM, KLX)
+GSC = (MMS, TDR)
+XJT = (VDD, VDD)
+FDC = (SKP, KXJ)
+BVQ = (XCP, XFG)
+GGH = (CSL, SBV)
+BMV = (XCT, KCR)
+QSM = (DKP, TBH)
+TKL = (KCR, XCT)
+CLF = (DHL, VNG)
+PBF = (PPD, TBV)
+GBF = (VGV, VPP)
+NCX = (XJT, CTJ)
+DMG = (LHP, CTS)
+MXD = (PDN, GTM)
+QBM = (KKF, LGC)
+SLV = (BGT, CFB)
+BRH = (QMQ, KCP)
+XHJ = (BRS, RFV)
+MXR = (FDN, CJB)
+RJK = (CSL, SBV)
+GDX = (DTK, JDF)
+VVX = (VRH, RBM)
+BGH = (MDJ, LFQ)
+HKZ = (NPF, FCJ)
+NLJ = (CDG, NBT)
+BTG = (KXF, GCL)
+QBK = (SPV, TPB)
+SHF = (FGT, RNL)
+XQF = (VHN, QVB)
+JKS = (GGJ, FGQ)
+GRF = (HTB, CJJ)
+LNR = (VGR, DPS)
+XTD = (DGD, NXR)
+GQC = (VGB, VRK)
+KCP = (DMG, QRV)
+XCP = (MXD, FVD)
+XXJ = (DHK, GXD)
+VVS = (DJF, VFF)
+QHG = (BQK, JHJ)
+SLT = (PMX, HSS)
+PDN = (KLX, DXM)
+DLT = (XHV, PMS)
+KKN = (FTF, FCX)
+BLX = (QHG, LHJ)
+GQH = (VDG, PQN)
+VLD = (FGX, HVF)
+KKX = (GQT, QXD)
+KKJ = (BGQ, LFM)
+LNJ = (FNL, HMG)
diff --git a/src/day08.rs b/src/day08.rs
new file mode 100644
index 0000000..580628d
--- /dev/null
+++ b/src/day08.rs
@@ -0,0 +1,166 @@
+use std::collections::HashMap;
+
+use regex::Regex;
+
+pub fn run() {
+    part1();
+    part2();
+}
+
+fn part1() {
+    let input = include_str!("../input/day8.txt");
+    // let input = r#"LLR
+
+    // AAA = (BBB, BBB)
+    // BBB = (AAA, ZZZ)
+    // ZZZ = (ZZZ, ZZZ)
+    // "#;
+
+    let (instructions, rest) = input.split_once("\n\n").unwrap();
+    let links = parse_links(rest);
+    dbg!(count_steps("AAA", "ZZZ", instructions, &links));
+}
+
+fn part2() {
+    let input = include_str!("../input/day8.txt");
+    // let input = r#"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)
+    // "#;
+
+    let (instructions, rest) = input.split_once("\n\n").unwrap();
+    let links = parse_links(rest);
+    dbg!(count_ghost_steps(instructions, &links));
+}
+
+fn parse_links(s: &str) -> HashMap<&str, (&str, &str)> {
+    let mut map = HashMap::new();
+    let re = Regex::new(r#"^(\w{3}) = \((\w{3}), (\w{3})\)$"#).unwrap();
+    for l in s.lines() {
+        let l = l.trim();
+        if l.is_empty() {
+            continue;
+        }
+        let captures = re.captures(l).unwrap();
+        let (_, [node, left, right]) = captures.extract::<3>();
+        assert!(!map.contains_key(node));
+        map.insert(node, (left, right));
+    }
+    map
+}
+
+fn count_steps(
+    start: &str,
+    end: &str,
+    instructions: &str,
+    links: &HashMap<&str, (&str, &str)>,
+) -> usize {
+    let mut steps = 0;
+    let mut cur = start;
+    for c in instructions.chars().cycle() {
+        if cur == end {
+            break;
+        }
+
+        steps += 1;
+
+        let link = links[cur];
+        if c == 'L' {
+            cur = link.0;
+        } else if c == 'R' {
+            cur = link.1;
+        } else {
+            panic!("invalid char {}", c);
+        }
+    }
+    steps
+}
+
+fn ghost_starts<'a>(links: &HashMap<&'a str, (&str, &str)>) -> Vec<&'a str> {
+    links
+        .keys()
+        .filter(|k| k.ends_with("A"))
+        .map(|k| *k)
+        .collect()
+}
+
+fn count_ghost_steps<'a>(
+    instructions: &'a str,
+    links: &HashMap<&'a str, (&'a str, &'a str)>,
+) -> usize {
+    let starts = ghost_starts(links);
+    let steps_until_end = starts
+        .iter()
+        .map(|start| count_steps_until_end(start, instructions, links));
+    lcm(steps_until_end)
+}
+
+fn count_steps_until_end(
+    start: &str,
+    instructions: &str,
+    links: &HashMap<&str, (&str, &str)>,
+) -> usize {
+    let mut steps = 0;
+    let mut cur = start;
+    for c in instructions.chars().cycle() {
+        if cur.ends_with("Z") {
+            break;
+        }
+
+        steps += 1;
+
+        let link = links[cur];
+        if c == 'L' {
+            cur = link.0;
+        } else if c == 'R' {
+            cur = link.1;
+        } else {
+            panic!();
+        }
+    }
+    steps
+}
+
+fn lcm(xs: impl Iterator<Item = usize>) -> usize {
+    let mut a = 1;
+    for x in xs {
+        a = a * x / gcd(a, x);
+    }
+    a
+}
+
+fn gcd(mut a: usize, mut b: usize) -> usize {
+    loop {
+        // let q = a / b;
+        let r = a % b;
+        if r == 0 {
+            return b;
+        } else {
+            a = b;
+            b = r;
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_lcm() {
+        assert_eq!(lcm([4, 6].into_iter()), 12);
+    }
+
+    #[test]
+    fn test_gcd() {
+        assert_eq!(gcd(10, 50), 10);
+        assert_eq!(gcd(252, 105), 21);
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 1d402b4..6a3b059 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -8,7 +8,8 @@ mod day04;
 mod day05;
 mod day06;
 mod day07;
+mod day08;
 
 fn main() {
-    day07::run();
+    day08::run();
 }