From 812fa7498c38e5465c523d1944b83a3d411941b4 Mon Sep 17 00:00:00 2001
From: Rhiannon Morris <rhi@rhiannon.website>
Date: Sun, 6 Dec 2020 10:13:36 +0100
Subject: [PATCH] day 6

---
 aoc2020.ml  |    3 +-
 bracket.ml  |    7 +-
 bracket.mli |    6 +-
 data/day6   | 2226 +++++++++++++++++++++++++++++++++++++++++++++++++++
 day6.ml     |   89 ++
 misc.ml     |   17 +-
 misc.mli    |    6 +-
 seq.ml      |    2 +-
 seq.mli     |    2 +-
 9 files changed, 2344 insertions(+), 14 deletions(-)
 create mode 100644 data/day6
 create mode 100644 day6.ml

diff --git a/aoc2020.ml b/aoc2020.ml
index 79a1553..b2b54b5 100644
--- a/aoc2020.ml
+++ b/aoc2020.ml
@@ -1,7 +1,8 @@
 open Aoc2020
 
 let days =
-  [|Day1.main; Day2.main; Day3.main; Day4.main; Day5.main|]
+  [|Day1.main; Day2.main; Day3.main; Day4.main; Day5.main;
+    Day6.main|]
 
 let _ =
   match Array.to_list Sys.argv with
diff --git a/bracket.ml b/bracket.ml
index 6dcca24..cc4440b 100644
--- a/bracket.ml
+++ b/bracket.ml
@@ -13,6 +13,9 @@ let infile_lines ~line:f ~of_seq name =
 
 let infile_iter_lines ~line ~iter = infile_lines ~of_seq:(Seq.iter iter) ~line
 
-let infile_chunks ~chunk ~of_seq input =
-  let of_seq seq = Seq.line_chunks seq |> Seq.map chunk |> of_seq in
+let infile_chunks' ~chunk ~of_seq input =
+  let of_seq seq = Seq.line_chunks' seq |> Seq.map chunk |> of_seq in
   infile_lines input ~line:Fun.id ~of_seq
+
+let infile_chunks ?(join=" ") ~chunk =
+  infile_chunks' ~chunk:(fun lst -> chunk (String.concat join lst))
diff --git a/bracket.mli b/bracket.mli
index 40ae1c1..aa129b3 100644
--- a/bracket.mli
+++ b/bracket.mli
@@ -7,5 +7,9 @@ val infile_lines: line:(string -> 'a) -> of_seq:('a Seq.t -> 'b) -> string -> 'b
 val infile_iter_lines:
   line:(string -> 'a) -> iter:('a -> unit) -> string -> unit
 
+val infile_chunks':
+  chunk:(string list -> 'a) -> of_seq:('a Seq.t -> 'b) -> string -> 'b
+
 val infile_chunks:
-  chunk:(string -> 'a) -> of_seq:('a Seq.t -> 'b) -> string -> 'b
+  ?join:string -> chunk:(string -> 'a) -> of_seq:('a Seq.t -> 'b) ->
+  string -> 'b
diff --git a/data/day6 b/data/day6
new file mode 100644
index 0000000..cb968a1
--- /dev/null
+++ b/data/day6
@@ -0,0 +1,2226 @@
+sukewbthnjdyv
+sjubpeyvx
+ouehaytkgzbv
+qfueimylvcrb
+
+foyedvcm
+yfodemvc
+cydvomef
+fdvmocey
+yvefocmd
+
+yizvxsnrhafmulctdp
+zvpnhusixraejywfcmt
+fxaiustovzhnkmrypc
+btcfymhrnapuvxwdisz
+
+csiquwmeg
+jwmceusgq
+cwsuqgzea
+tudevlosqcbwgxk
+qewisgucr
+
+knbiqdemv
+iknjmph
+yxtzsrumonk
+gkwmndqv
+
+lmtuq
+lmt
+jultm
+wcltmegbk
+otmql
+
+muw
+neumw
+rmuw
+mwu
+
+kpqbneys
+kqebynps
+syqenpkb
+qkneybps
+bypkesnq
+
+wguysaop
+suyphabtmocg
+prygsowua
+
+zikctl
+spqelxygof
+jlm
+zlim
+hlvb
+
+ejnypwcmsutbdkqf
+swfptbqucykmdn
+
+qgcmfhdspiywu
+csuihkqpydf
+icqasudphfy
+
+rcegxphy
+xpghcyer
+
+idljrsopehmn
+xkzguawebtvqf
+
+lohunty
+thonuyl
+olhunty
+
+v
+lvgze
+v
+
+z
+j
+s
+oae
+
+mngbsztec
+zmxsgtyoeri
+gseztm
+ueltqmfzgs
+etsmnzfgc
+
+zqmbvy
+yq
+oyq
+
+cyhaeltuxkwfzgo
+wdoqfjltnipsvkcxhyze
+ytzkrlwohfcex
+yhzetxbcflokw
+
+vtxjhymsfcw
+swtmghqzfv
+vwtmslhf
+ftzhpdrknwmovas
+mvwfbhtus
+
+povrg
+gvr
+rxgv
+
+npymvdcjhkz
+cygihpjndmkzv
+
+pz
+zxpu
+pahz
+oypjdzn
+cmpz
+
+vup
+vud
+vu
+uv
+vu
+
+jzqwy
+qcrsjubnd
+jnysqduf
+qtphglmaejiov
+
+fsyhkgw
+guypskhw
+
+obdj
+ibv
+
+lrt
+kzafv
+
+ozax
+l
+l
+l
+w
+
+lzbdyveqpj
+ekrocfbags
+
+hidv
+hixduv
+uvdifh
+ndivzh
+gdhcvtime
+
+mdyrbfujolche
+qvldabjmuc
+
+o
+i
+e
+
+cwjoesuyvbmfx
+yzafdkcevjglshobmx
+ofscpvjrinxeytbmq
+mvxcfuesywjbgo
+
+jolexqn
+ejpbn
+jzespnb
+
+rklhfdmpvixqzebsjatwyg
+sqfjzhgxketiplamvrdyb
+
+tkrxoqu
+lruqo
+arpuzoql
+rluqo
+olraduq
+
+s
+s
+s
+
+upyzxrmgenk
+iumrzpncxey
+pzicymnerux
+
+skxy
+xzkmy
+rtaepyck
+zkmyg
+
+kuymqh
+xyqmuz
+qmykue
+oyfbqum
+
+t
+u
+cqs
+il
+jhl
+
+szrhdwe
+olr
+gr
+fypmtur
+hnglzr
+
+quv
+unpr
+fru
+ru
+
+tdkybancpfmvhez
+igbouylstjxwr
+
+vckofs
+kvspnfcbyg
+vskfcer
+kcsvfj
+
+bevcrslyfopmzkjng
+dsvoeflrzj
+rfjesolizv
+xqroevzjsfl
+
+k
+eb
+o
+m
+x
+
+gxulbvfnj
+nvfxugj
+
+liqcxnv
+vxlfqn
+
+o
+o
+o
+o
+
+ynsowejdq
+fuzrxmls
+
+necsvqwyxfzbur
+fomigbkasyunhvpt
+
+k
+kv
+k
+
+jlnscagkozwm
+ctgmlznwkas
+ewgjcfmsnzlka
+scluzgwkxabnrm
+
+rmfviobzuekan
+gztioywe
+
+ihxumnvtajswgbl
+bvsitkamwjhgxul
+agvhjwusbxlitmzo
+yhdxewivbsgrcqupajmt
+
+azrmjwki
+mikzjrwa
+
+podwmavyujf
+jvtawfoyudkp
+apyovdijfuw
+
+nqyvc
+cnvy
+yvnc
+nvqyc
+aycnwfv
+
+go
+nv
+zs
+rbmda
+
+laixtnkeqvjr
+tfagkclver
+
+w
+wz
+
+ismtrejyqhzncko
+zctksyemvhqin
+ztiqaynludkscxhm
+
+lqtowzfpau
+pleajiht
+snb
+
+xmilskwayjtdgcuzfpbr
+akmpqrbotzgswcjuy
+jytkoezhmrpbcuswag
+qzabcgksjeyutpwrm
+
+bzv
+byz
+kszb
+
+repd
+nqplacx
+pert
+
+qjax
+sqzikvtuc
+
+jbvflcxmkgeuiqshwdon
+ehojsklfxngmvcidwubq
+efmilsjwgqunxvochdkb
+
+asbcpe
+pecsabv
+sabucpe
+cbspea
+
+puazdrxn
+huodn
+ul
+bhxtalj
+ewqgkcfmyiv
+
+mkzlap
+gkuejz
+vckdwty
+
+bgwuqlcpye
+ruyplegbc
+ebgslpyuc
+
+rzxjahqkdm
+qsvzl
+fqzl
+yqzs
+qgivz
+
+oz
+z
+rgz
+
+qeodmnwfrcgszxljpbtiva
+bxfmsotjiwahdreyqcgznlv
+rfgoacmsvtdlxiznbwqje
+isnrctlvbdjeogxqmfywza
+
+k
+ok
+ndk
+k
+k
+
+kvlaxjyuizosc
+rskivnuzdgylcax
+yeulqahszikvxw
+
+njcgolfwi
+nbvgpfwjaoislt
+ngifljcoyw
+
+kmhe
+jtkg
+
+rwxcsfokl
+owikfaxpc
+njoxkwcf
+ackfwox
+
+ur
+ur
+ru
+
+fdywlphcigkqo
+thuynwzra
+
+yg
+yg
+yg
+yg
+yg
+
+lgujzisehrmfvpqdtwx
+kpxwbjsrycvmedotuna
+
+caoqxmnz
+znmoqax
+
+n
+n
+n
+
+dl
+z
+z
+z
+
+myxjup
+xapmujy
+pymjxu
+
+armiuvky
+rukyvmai
+
+oblmhucy
+lor
+oadzwlv
+
+gmuhklsdpeifwjzyx
+ujhimzlwxpkdfcgye
+hdzjyexbmfukgplwi
+hjfiugmzlpwnyekxd
+uwpozylxmhkgjdfie
+
+egvotzkidfbschnwj
+cuojhenkdtgivfzwp
+
+sydwoxjtrgeilkpq
+wlisqzgxyjdepo
+yjisgwoldqpxe
+
+ziu
+vbcli
+dhti
+gik
+iu
+
+wsaqb
+fdhmkv
+oqzeligb
+yxagtq
+
+hgxnkmtczelbiywdu
+egdlkbhxinzwmtyuc
+
+zylwnjbpxfikgma
+uyiwbalxjfpnzkmg
+
+fdk
+zudwmolx
+iuwydo
+
+ipg
+gpk
+pg
+lgp
+
+qo
+oq
+
+ftvpzxbnrcaejlsughokm
+pajgbomszrvlkthufncxe
+rcvkltzomsanehubpgfjx
+slpnugxkvbtofcjzaremh
+mevnxbcwlofphgjzustark
+
+imqpfwxzdbyej
+befpdqiwymzjx
+jbweqdizmxfpy
+mdifjqpxwebzy
+fqpwyzejxmbdi
+
+xcgqsnhjfewkitrdbl
+ikexjmzqghfuwb
+
+xvlt
+plxizgt
+canruewkof
+hdv
+ph
+
+selthipryzdjaqo
+mwvgfsczjx
+
+lkvhrmfxcei
+dlxeikvrhmc
+bcivhjuletrx
+
+hameyvutcq
+ceimstquyha
+tcvmheuaqy
+qtycuimhae
+wtexqymuahc
+
+aqi
+ahqi
+iqa
+aqli
+
+dqsyvxihlnapkugfet
+avhylqkigpntuf
+uyogpqtznfjablvkihw
+
+ujteibs
+jnmse
+
+lcark
+kcalr
+raklc
+clkar
+
+pdriy
+dypir
+rpiyd
+iyrdp
+iurdpy
+
+xqfiongludk
+mgthdfqcjislw
+gfrodulibnq
+eqiofgld
+dialxyfqg
+
+nuglmj
+yglmejodvu
+pguymjl
+ojmuzglb
+twqumlhjkirgxc
+
+zvcfwmxr
+mtwlcnvyr
+vmwrtc
+
+fnegrtvcszb
+fvtczsbrglen
+regtnblzvc
+qvetwrbjngzc
+rztnsvbcge
+
+c
+c
+ic
+
+ytafbngdrwkmsizu
+mtbarufinsgdwz
+buzgnmfirsatwd
+gmfdwaivrupstnzb
+
+wmiugpfxvaqy
+mysauioxwqp
+wxmupiyqa
+iualopmhywxq
+uqxpiwyaml
+
+rfoazmhstpwu
+ylhdagctoszuv
+tnouzbsixja
+ethsavmwoquz
+
+rusvk
+sukrv
+lsurvk
+ivarksuj
+
+vtonlxkefpmhc
+toxnmplkvehfc
+lxepkfohnctmv
+lcfpwvkomnxeht
+
+k
+uk
+
+masqlgwvbzthjfodi
+qidwstlzhmgbvjfa
+walfgtjbimhsdvzq
+jgvqfidzwhtlbmas
+jfbdtsqvwhzimgla
+
+ycghqoakjvledit
+cvogqadtylxheikj
+dlikveqjytgocah
+qjogltyvkdiehca
+hqctvekdgoaiylj
+
+qmfszexayhrodlkjgcunvpb
+azkcfvgbqhwntisemxojlurpyd
+mahdrunjvogfszeklqxcbyp
+
+afneqblchsiztjkormgwyv
+xtnekyjawmcgboqzhlvpr
+
+sx
+jdbx
+lx
+xh
+xa
+
+rdjilzeufkawpynthm
+uihatklnjrwyzbefpd
+
+xamycgrp
+odcxabirgyp
+yrxgnpca
+rpcyhxiag
+carjykfgxp
+
+qfzjcxvngr
+vxjrngcfzq
+fgvnzxcqrj
+
+pndiwz
+ziwnpqd
+hnckpziuw
+iwpnza
+
+oqg
+n
+e
+
+xiqkbmeunpgz
+qkunzpgexmbi
+buzpqknhsegmxi
+gnqzekimpbxu
+
+hw
+hwqy
+
+nikreb
+beirkn
+rekinb
+ikenrb
+briekn
+
+ygu
+yug
+uyg
+guy
+yug
+
+qa
+aq
+paqt
+qlaei
+qmuona
+
+eikhtowu
+ucqt
+dblxyj
+
+h
+h
+h
+
+efachl
+lxwseg
+kdvcotebwl
+urmzieqypnj
+
+xim
+mix
+
+yueg
+rfuqv
+hcuyt
+mwdxoijl
+pu
+
+dt
+d
+d
+dg
+d
+
+njpbavcqi
+apbvnci
+xitcnkavbp
+jvpbanic
+
+ihafgmuzlsecyw
+wilkugsacehmfy
+hmsogafiycewl
+yasifqwghmpcel
+sewfmlgaichy
+
+bwzqplsndam
+npablswzmdqr
+mznawdpqlsb
+pmqnwblasdz
+
+bstnjrdih
+mzqg
+auvxom
+xfl
+xwzeapqcyk
+
+biylorc
+jehr
+
+klsmr
+bsrulm
+sulrm
+lmcysr
+
+ryhfwom
+ylfprowhgs
+whdayfro
+rbfhwxqyo
+ofhrwy
+
+bjsotye
+btykhedw
+
+ytfvapsh
+wgrvpyahkf
+fyhvpa
+vyhstpfa
+
+a
+ak
+am
+
+z
+z
+z
+
+kvzfwneupotmcgldhjrx
+mdkwnevctjxlouqrzhfp
+
+ipwgoe
+poegniwd
+
+mptxh
+umj
+yegdkrizcvb
+
+bea
+e
+e
+ey
+es
+
+acbzkvrhujltyqf
+htvcaqgkfiulbypezrj
+aqkfzthjbyuvrlc
+yaqtzlkhcuvjbrf
+
+ilgschjkmxuy
+qtiywjlcx
+lfcjyqxoiv
+
+e
+e
+e
+e
+
+vtaiyrfpj
+jtpmvfyra
+pfrytvja
+
+kmlxghip
+mhldpg
+mghplq
+mhpgl
+
+glv
+sugfl
+klgdib
+glw
+
+xteusvw
+euxtvsw
+wvbxteus
+wmsxtuphveq
+
+cdzjibqkytax
+jkbzxdiyqnct
+
+zankicousdgtl
+ustgdaniczokl
+okulsgtdaincz
+ktsocladiuzng
+
+inau
+naui
+iuzmpan
+uina
+ianu
+
+plbuxck
+clfpxkbu
+
+ryxu
+yru
+dcrjyiu
+ryu
+uyr
+
+vgwrjpsxhqn
+fdqpn
+pfqn
+pnuqt
+
+wahxceymdtj
+ycdmjaxwhet
+emdtaychxjw
+dewhymjtcxna
+
+gbua
+nkw
+
+fz
+z
+pz
+bz
+zf
+
+jlfeonbgdutm
+nebtofdjmlgu
+ldugbeynfotmj
+fmlutjobegnd
+
+pdkzowbuflqgt
+twbolqufpdzg
+
+cyeuvjtbinholfx
+cjhostyevfnlbmi
+
+x
+bx
+x
+xa
+x
+
+rudlgmtnkc
+oqbxv
+o
+
+vyasowhlpgdufrqbenxt
+batgwhlsqufvopenryxd
+xtyrenhpvafgbsqwdlou
+fhxanltgworqbspdueyv
+twpyqnuvgerxbhldafos
+
+mvcb
+vcm
+vcm
+cvm
+mvc
+
+ycaplgozxd
+daoxlgczpy
+
+b
+b
+b
+x
+
+fz
+f
+krjeaxmf
+f
+fz
+
+vcbm
+vwsgef
+evln
+yqiuhtkzrj
+
+ng
+ng
+nlj
+
+acoplfbrxjgwutq
+jrwocqlfatxubp
+
+oszjfuv
+dslu
+pxdus
+
+zubdqopa
+dbuapjnqo
+buiadoph
+ojawubpd
+sofpmrudab
+
+ct
+ctyx
+gtc
+ct
+tc
+
+j
+j
+
+hdqgvk
+vqkdgh
+qvgdhk
+
+fmgpbxdwyiqj
+bqywxfgjimpd
+
+dxmuvetajoysibhqg
+nxedgmqvipytbsurjo
+
+eubkmnpz
+hxmvufkibnz
+kbudmowsz
+inrzbmuxk
+
+hqje
+ejhq
+heqj
+ejqh
+
+y
+y
+yc
+y
+
+nmsgowetayil
+hpvbdqnckxj
+
+zyj
+zdyjk
+yzj
+jypz
+
+qgpu
+qg
+
+fu
+xs
+omw
+
+w
+agd
+dx
+tezoc
+
+erqkcxt
+sdpmvilozyan
+quc
+gxbhqr
+
+tdeqmjigaywlvsrn
+imsctqvnrdwjlgyea
+vunkwyhibsrgmxaqtldzej
+
+qxpnhkyz
+hnypxzqk
+qphzxynk
+pzyqxnkh
+ynzpxqkh
+
+bue
+bue
+ufbmeq
+
+neg
+e
+ksxo
+
+fgdkuwm
+grkfu
+
+c
+c
+c
+
+djqksy
+syqjd
+
+uqvztgcy
+tuzvcb
+jztuvce
+ctuevz
+zuovtc
+
+phlbum
+bhupml
+uhblpm
+aplhbmute
+
+gbiwk
+gawxiek
+gkiw
+glkbiw
+giwkl
+
+xepwdgfrytajinhoq
+rsaotezjgucnlimk
+
+oficy
+yca
+ycd
+cyg
+yc
+
+lub
+cblu
+lruxnb
+
+nbwcmqa
+xbnqwcam
+nmbawqc
+wnacfqmb
+
+cvounwyxtmrfdhjbsla
+tvdmxjhqucaowbfsnlr
+
+uhcdfzsgxwtejkqo
+hxzcquksfgeodwtj
+osezufdhwqjxtcgk
+tcewzdjoqghxuskf
+qgzhsujdxwoeftkc
+
+xvhboqlgrypjf
+hftqjpxguyolvb
+jxvqgyfacopzbl
+
+hqosbywltnagkzpudirjcmefx
+hnmuldwyxcpfsbrzkgejov
+
+ghtvjnuwldzx
+vsuzahjwmnd
+pzwvuctijlndh
+qwznuybvjheofkd
+wdusnjrzhvt
+
+zuphrg
+puhzrg
+purhzg
+puhgzr
+
+injtqw
+niqtj
+tjpncqrzl
+stqjn
+tgjnwq
+
+ogrqaclmytjspwuefz
+owpcyrqgatmfueszlj
+qeprtazojwlghumfcsy
+syfclprwjzauogqtme
+mltuasgyqjeopzwcfr
+
+vwczioq
+wnlh
+wn
+hfnw
+
+xpamkfbv
+gytnslei
+zhcswj
+eznydrt
+
+gwnxykecs
+sxenkycw
+yknecwsx
+
+arsyvxtn
+fpkejwcuog
+lxzsdhirmqbn
+
+deoi
+byeanvt
+idple
+
+gtjhvn
+ukny
+ltnm
+qofsadewxcb
+
+jsfxod
+bcqyxzd
+xdpomwnt
+
+wxdypceabjtigruhmszv
+abyxhgtevjpmwrczuids
+czvgbhrtjxsaiydwpmeu
+aybegztxsihrcjpvwumd
+ztdeimhryjxwcsbapvug
+
+awk
+wa
+vwa
+aw
+
+kh
+gk
+
+orhs
+ohqrs
+srho
+
+cdseliqzmxr
+putwvjigze
+ikzvanwe
+pgazjie
+
+lj
+jl
+ljc
+jlr
+
+fcjtuhaokiex
+eoxhfqukzitcjanw
+xjoutkphcfdgsial
+
+diqvuj
+vdquji
+xudsiqjv
+dvqjui
+uvdijq
+
+sgyjcewoqmtknir
+njcueswamtrgkqoi
+srinwekoyqtcmgj
+qwxbrjkehgfvcntopszimd
+
+ihudyzfgvplqjawrtemcsxkbo
+wmfdbjzxtkiruvyqscphelago
+qspaetibkfdzuhmlxjwryovcg
+pfgykiqajmoezudwhlrcbvtsx
+qbweptkonashfgrjxuzcdlmivy
+
+tqpnysgxbrczi
+ewungkavbzoqix
+
+dnatolubrm
+gykvdnqblero
+rbndolsm
+zlbdrosnf
+arhlbnfuod
+
+bof
+obf
+obf
+
+sfowhkxidyu
+dsyxfhik
+khxdgsfyi
+
+troasbmedwuc
+bakeputwdfmycos
+bmvwlngheqsctazujodx
+odbafecmtwsu
+
+svugapj
+hupsjv
+uspvj
+vuspj
+ysduvhjp
+
+epvkocuynsdgxabw
+askfqcwevpudxlngby
+jwxcvbyghdsauekpn
+
+uxomkrnqbda
+bkdaxqnuomr
+mnqxkdubrosa
+qmrblxndkauo
+daqbknurmyjox
+
+fdmys
+ydmsf
+fydsm
+sdmfy
+sfmdy
+
+kwyios
+yksiov
+okqnlashy
+ogyks
+vkfmosy
+
+bwsa
+wbphsua
+nubotsaw
+ajscmwbf
+
+nhxec
+ubdkivs
+
+eatgmjflvkbpqyroszuidchnx
+vndrhqzbcfkxouemjgltys
+dbhtvucnwfmylozsejkxqrg
+
+sizuofhdl
+chdztjpym
+xhzoebd
+abhvzsd
+
+wepdrksjizqxa
+jdegpilxkrzaswq
+kvpybqrxdszjiuamwe
+sqzdijkrxpeaw
+sijqpzxkaewdgr
+
+bhip
+bhk
+
+ynfhorsbquxicw
+ufgrcnsixybhqow
+
+ivopdlxhzysjqncw
+pukfrqxish
+
+gwfmuntbicp
+dwgsmfntbxzuq
+teumifngbw
+ghtnbuwykmf
+
+ayrwtqmpvhjnfbo
+fybqnxjrswakto
+obglufdeitqrncza
+
+wynjtzfvdpiahxlrubksgqm
+pxqgkjtbdhvyusnlzmwafri
+yjlnqcrzsbtumvkfiahxwpdg
+
+bcfmw
+waezsm
+siwgz
+ovtrnduhqwl
+wciex
+
+dsiekwvym
+dswemtyvaik
+vsmkewiryd
+dyewiksvm
+mydelvwaski
+
+jinutyhcm
+dvymgtpbxj
+
+ekyambt
+etabrngkcy
+hoayktbe
+
+vypd
+xgfhle
+
+idkwmoephjnlvfa
+ecofuiknpalt
+euacykbifporln
+
+ogyxzvnr
+gozynv
+nvozyag
+vnozgy
+zyeovgnq
+
+tgplxrfdnuzqme
+ugktcxpmrlbdf
+xlvmyfbcdghprtu
+
+pbgueijkfax
+aufjegikx
+
+l
+ly
+l
+l
+
+awmdfvtrlybucg
+vtfwubmrcgld
+cldmjtpurkwgvzbf
+
+l
+l
+lk
+
+qkpouawef
+cqfgkbameixo
+ouaktqzwfje
+
+camibs
+tcyd
+ndgxc
+pcwlt
+
+pfbnrxzywviot
+ypgrmixowasufznvj
+
+lzbyhnwsgdrxomai
+omlyzanbhvgiwdrs
+lborwhziangsydm
+
+bconaghpkfzvmy
+qhyxogapvkfmcn
+kcgfuhympnvaorw
+sthkfoncjliapydvmg
+kqvnoempghucyfa
+
+zixq
+qzxi
+xqiz
+lqimxgz
+xqiz
+
+w
+jstq
+xkphoue
+fzjv
+sgwt
+
+ocl
+bctnamsyhdfr
+ce
+c
+jclip
+
+aywt
+pt
+
+on
+nho
+on
+
+wyikztj
+zecdrxan
+psmubwzvj
+fzhmkq
+
+bwtuvk
+uvbtkc
+uvkpto
+mtqykvsjrgiu
+twovku
+
+m
+m
+g
+s
+
+pdmuxeftk
+szvgeotcrwbuq
+
+ibvgkput
+iugpkvtzjbx
+
+skzuqtbiaedovwhlrpfnygxj
+yqfidorlkwhgsuptzemvx
+boelkavqwrtxhzgifypuds
+
+o
+o
+xo
+o
+
+bkpjouw
+cjoklhbw
+ehukwbo
+bkfxynqrgo
+iokjabw
+
+kceugzapxfmisljnwhtrbd
+gfzhwrbkdcliuejsamntxp
+msdkgplhfrjucetnwaxzib
+ktsrinlcaedfhzgbjuxmwp
+bwguhamrtfkeplicsxnjdz
+
+lz
+l
+z
+u
+
+mwsuaicld
+saiwmludc
+sciamwdlu
+sdawuclim
+
+zvb
+zpv
+vmdqr
+
+djr
+isjdr
+
+ybek
+rkl
+fgoknah
+kmij
+qktyx
+
+oulpwbgy
+oalwgujy
+ehflnwckxgosrdizum
+wvloug
+
+vcuxtb
+vcux
+vuxc
+cixvu
+
+tyczpjsn
+szpnjtcy
+zpsjytcn
+
+hurjk
+krhuj
+khjr
+vrhkj
+
+befydcomjzpi
+vpejdyb
+darbfeylcpjg
+tnyuekwqbjdh
+oexdbsyj
+
+d
+d
+eiyd
+d
+d
+
+anhoyr
+hn
+hrna
+hkxpnifbc
+
+yapmothqvzxkwbgufe
+ojwbmysdi
+bdrmycwosl
+wnmyob
+
+qkjznrdpsfbocmuaeihwlv
+jbsumpqahtlwdczfrkv
+jlpcqbhfduzwkyrsvtma
+jxdqhacvzpwsgkbfurltm
+
+cr
+jxsqu
+wc
+
+qzsgdceyfuwlkjrmio
+idlcywerqojzkmgfsu
+tsokrqumcawlefyzgij
+kulosgvhzqrjfiywcxme
+
+tfpqmobildwx
+cnawmups
+
+yuilzhtrpvkq
+tvucoih
+bjgafmenxdsth
+
+opzulrejdgqhwftvbn
+yozgtenplwrvjbfdu
+urobdigfwlnpvjezt
+
+jeatvniymqcogupsxfwd
+qedsypugotcjvawfmixn
+dpqyseiajuwxmvofntc
+pxamvsucfwoyqjhitedn
+xsuypaovrlqjewizfcndtm
+
+vugbznlqkixady
+dvoejyxcfzbrmas
+
+mwsklah
+ahksmwl
+bmwkhisla
+ahlwsxmk
+
+srfqb
+sqbrf
+qrbfs
+sfqrb
+
+xhvbocnpwgaqylirsuft
+onrypglqxfibhvwudska
+opxvsfniwblrqjhaguy
+reixqwnglhfyvbaspou
+
+linazro
+np
+n
+nm
+mwn
+
+gvbxwtsalpurfcm
+bwgacrmvxupsfl
+abfwpumxcrgvsl
+aluvmgfrbscxpw
+mlpcbxawsfrvug
+
+v
+v
+v
+v
+v
+
+nwdzilkeqogcjxybaru
+mcygaopwdrizkuxjlbnqe
+
+zocngjfxebvrwlsydqp
+oqvfclunwxsbrzpgjdy
+
+jvrglxbp
+brlpvyjx
+rxlpbvyj
+
+voiuyjcdtgsnh
+cwtugdovkhin
+bhnatyoxgvmcdiu
+
+ikfl
+li
+
+wt
+wztjqy
+wt
+tdwsau
+wt
+
+owkszmhcqdeb
+rpyaswvxclf
+
+aqxneirmc
+mnqaiexrc
+qxcaemnir
+eqxmniarc
+nzeaxqimrc
+
+obefhjkmsyl
+fgcdqwvzypur
+
+jv
+jv
+vj
+vj
+jv
+
+vesgfhmrox
+exmfgsrvh
+nfyirshgjvmex
+
+hyabitjszvupmfor
+ierfutjmhbs
+hjxinstkfcqb
+
+giqrzmfsuxcehvldkabw
+iqfsgzbxlvawhmudcrek
+
+top
+yjqvk
+vqx
+
+qpdiksm
+dkmiqs
+msdkiq
+
+olwkfxdpehmj
+kdfpeomljhwx
+jplxoewmfdhk
+jpkeowhtlfxdm
+qzkojefdhxpwmlu
+
+sxjwrpgqeciz
+vnkcujwhidral
+mejsrxizocbtwy
+
+qojeghzvlkn
+kqonvcjeghzl
+vokgqlzenjh
+vozhjlnqkeg
+kljohvqgenz
+
+dpwyhufkvaiqob
+dpuanijkbqgy
+alkpqbsrtide
+
+wcju
+wuqgs
+ampdbnzwufok
+wulcyq
+
+izojdpfgke
+zpeokgdijf
+epfgkiodzj
+gdefojzpik
+
+wjqpblyt
+ajbqpwflvty
+jpqywblt
+bqlwjyztp
+
+brej
+jre
+herj
+jre
+
+myibr
+rbimly
+
+gmwbanlupcxjkrtsfqieovz
+ieuamrzqvsxctbnojgkfpw
+cvstxzkmgnqiaujfporwbe
+
+si
+is
+usi
+
+hsuqefpd
+qrupshdg
+dsuhpeq
+quhpesd
+qpduhls
+
+djewcplsmbnykqfuhv
+bkgucwsvymaei
+ykvzmscurwbe
+
+ifpavbtrzjlyesqdgkhxu
+qzyalxeunimdojgbf
+awyuezqifbgjxldm
+jmeydfgiblxuzqa
+wjnuxzdeagblfiqy
+
+e
+b
+
+lwx
+w
+whi
+
+xqomviapj
+myqcvo
+
+vaidsjrbgouhw
+ynufzsqepdtx
+
+ier
+eir
+ire
+eir
+
+q
+q
+q
+kq
+gq
+
+gdlnrpjwbkmcy
+pledjybncmw
+nwdbpcmljy
+cyzofudwptlbnxjm
+qmybdpchjlnw
+
+guxvnk
+bvgztknx
+gvsjpxrknfe
+
+tkc
+tck
+ckt
+tck
+ctk
+
+tcvihysmdwjfuz
+hdjpkcyuetafxm
+jvmhcyuftd
+
+etvflsguxwqparh
+pqshwvikgutlraex
+ghrxultaqpsewv
+stmlauvhrxqgepw
+lthnsavupxqwedrg
+
+q
+q
+o
+q
+q
+
+p
+l
+fd
+n
+p
+
+kejbzgqhrwpsdmyluctaifx
+jbqyaksrwgpxezcthidlfum
+fithrjwagodsqzlycmxbkepu
+
+bjlktgunzed
+ezdtujbgkl
+oljkzbdxetgu
+jlgastdeubkz
+ljdzgtbuke
+
+b
+b
+b
+
+zcmqedjshfngwuta
+yczngvjfdkmuotaerhw
+quhjzdniftleagwcm
+
+uxokfse
+byseztxkcdpo
+xqresokl
+xskogven
+
+cpbfntrsqzdauvwmighokjl
+jnlzpgamuksvhdftorcqb
+dmktlpofhbczayusrgnjqv
+
+rywemn
+ney
+
+tnfmkwbr
+
+ieyok
+knyeo
+oeyk
+cmkoey
+
+fgeodaihyqrj
+aiyzfkdqhgj
+aqfzgydjih
+zjhgfiqyad
+fhjdmaigyzq
+
+jfsthv
+fzkshvet
+hsvft
+
+chjmnapvdlqi
+lqvpcidjham
+lhdctpiqujavm
+mavpbcjhildq
+mjpvalqdhic
+
+rxvozyjuc
+cvzxyour
+zyuvxocr
+zjcxvuoyr
+rcyvozuxe
+
+mkf
+sfmk
+fmk
+pmkef
+kmf
+
+myoakncviphrld
+vpkiycnradohmx
+
+yvdlnm
+tg
+uhdo
+jwfqs
+lozgrx
+
+flwcpvgm
+lvpfmcsagw
+vgwflpcmu
+glvswmacpf
+
+ujnaeld
+nclsuje
+nmejlu
+deunjal
+lequnj
+
+qveitg
+eiv
+vuei
+erlvi
+efvaipc
+
+b
+b
+
+blkdegxiuwpozmh
+mbielokudhzgwpx
+dewlugkxpmzobih
+edimgxuhlowpbkz
+odekxuwzmhbiplg
+
+agktcxds
+cstxadgk
+nxpdkcshuitrga
+dbtgskamcxvf
+akgdftcsx
+
+ap
+pa
+ape
+pa
+pktag
+
+cnxazmsefgqupvdjl
+ygwfsodp
+
+cobevtqrmpsfi
+esivcqbrtmopf
+mrscpvtieboqf
+
+nezfcvyqolapxdtgjh
+tjdcbnhpzwqe
+tzqcjnpehdr
+crnepdtzhqj
+jtcrbzhnpmeqkd
+
+uzcvrtfk
+utzrfvcbk
+vcktufrz
+ercpvzukft
+cvzuorfkt
+
+fhdvlupmyinrkg
+ykiapgmdluhvn
+vklipdybnuhgm
+
+gndywvfsrkmojb
+otdfbrynkwsvgj
+sdyjgobrfvtkwn
+yfrobjxgdnskwv
+
+jrcxmdlb
+clbrijx
+
+eabkotfyqicsrgluhv
+pxqzmaitgdjnhw
+
+mpydoxr
+odmpxwyr
+mrydpwazxo
+dyxzmrop
+drtpymxno
+
+irfveyz
+riyfzev
+
+envoajbhsp
+ayswzvnlxtjeoh
+jvwholeinqsfa
+
+gh
+mgh
+hgmj
+gwbh
+
+ymdjralcitnkwgsx
+xnilbdojkyfrmchtgas
+ukcatelqsxyrdpjvmigz
+
+xvbwsf
+rsbxvwf
+bvfswxaj
+swbvfx
+
+hx
+e
+
+jepqlufigz
+pxejfqgiul
+fxipqejlgu
+eljguiqpf
+
+fvco
+cotfvqxm
+
+kxpweshd
+wkxsdcpheyq
+
+ncfrt
+tnfc
+tfcnd
+cfjtn
+
+sgpcajvwz
+enulydokbixmh
+
+ft
+bjtmsf
+tf
+tf
+tf
+
+pgfuetm
+tmfeupg
+pmetfvug
+
+bts
+bstz
+
+rdfxyb
+xbqpy
+bex
+rqxb
+
+vj
+vj
+
+tfue
+gujxt
+fsnout
+tufnl
+
+jhpnewz
+rnqzwhl
+vhyznwkigt
+
+kcizgojlrnyhbetfmd
+drlcjtybkhmefionzg
+erihblomzdgkntcjfy
+nfmlrigzbejykdhtoc
+
+hbkfsjmpncuytgqd
+cewstfdnjgypmhqbu
+
+lnyupsfxzkdebhgwoamriqctv
+sqzptvgfcnworhuxiymbalde
+yflwhamutxobsdqncgpvezir
+qrysnohtbdzljwfvpgcmuxiea
+
+rkaqlw
+crkwuobal
+alwkr
+
+yehogdimsf
+levrtiphjcgdf
+wkeihgdsf
+fzqdesxngkhmia
+
+ovdmtba
+oamvur
+
+sfrwvczuopkjtldqyexngbmhia
+cayogtsqwbrimehvjflxknuzdp
+
+ghlawfdteobicxqu
+wacqbthguzfexoi
+couhigamqjpvfwtbsekx
+
+pznud
+nklpxd
+
+cpolfguxeaimjkq
+oaliefuxmkgwjqc
+ckiemqxagflowju
+yioqzuhcmafekjxrlg
+fogqkmileapxjubc
+
+odrtypjgnhuifmxv
+mfxpjnzhoitwygruk
+
+atmfbz
+tcma
+
+rfpesujl
+duxmejc
+jzxynvogtbdequ
+
+on
+on
+
+fwbvnmyh
+inmhfybvw
+bywmvhnf
+vfynwhmb
+
+kweqzphagnbd
+ftphezwngmv
+ugyncshezip
+
+zfxsrhdqjoyb
+jszhfrqybdxo
+brdxysfzoqjh
+rjfzxshyboqd
+rfxyzhdoqjbks
+
+mloyxu
+vfieh
+
+flswu
+bfozhsrw
+fsw
+kwfds
+
+qcmapueyrvzki
+xnthjgdwf
+
+avn
+anv
+cavon
+
+lvdhrz
+lvhzrd
+vhrdzl
+
+kthsozafpm
+nxaverjibgocl
+wmyuado
+
+mxwybevtsdkzrq
+rbsqweynkxzdmv
+vdyzbmqxejwrsk
+
+qw
+bwj
+vcew
+lw
+w
+
+djvk
+jdkvu
+kjd
+rdkcezj
+
+jvydnmoiszp
+bglirhwa
+
+icuzoqfdwbjlyhegapvsxt
+lypjieabuotxgcdhqszfwv
+hwyijspgabutldxvoczqfe
+bswhptyvefclugjodizxqa
+edihqsjtcxwpyzblfgvoua
+
+o
+gq
+o
+
+sb
+axro
+sw
+
+nmkyft
+fgktypjs
+ftvky
+fyztk
+tkfy
+
+dgkxmyeficrhualpnvs
+kefsldzyphnumvaigx
+vsxqoflupgmaidyenkh
+yluvxqpgndkaimfhse
+
+yhwckdbfujtpminaq
+qfjhgpukmcobwid
+fchqsrjxpvlzkimb
+
+wlhantpvmydbzjk
+nahtdkzjmywpv
+jevahszfprdkmwytn
+
+sfqcrtv
+frt
+frt
+tprf
+tfrh
+
+hvobcgqfdutm
+gamtpkcbqwvuhn
+uvbcqxhtgm
+tdmhgvbcuq
+fqmuchtvgdb
+
+jxoc
+jxoc
+jxco
+
+uzybvip
+dotieypbwu
+ikbspyugx
+
+eqhwdmtlizyvuksjbc
+keutmlrqxnbod
+rdqnmlbuket
+bdklqrfetmu
+
+byvhscwt
+cvwb
+vbwc
+cbwv
+vcwb
+
+qb
+ri
+o
+v
+b
+
+csfjmh
+hpqsfjz
+hsfmj
+jfhse
+jshf
+
+ubjpnxcoltzhrsmkiwva
+primkxnzljbtohcasuwv
+xrtmockuvzalwbjshpni
+bunwycjzgikhotsrvmapxl
+cvxsnpkairjhobtlwzmu
+
+wamkifotyqxhdcezjbln
+afihocljxnkwqdmtzyeb
+
+ysnukcpaxbw
+kpqbcwtumxysn
+lbpknsxwcuy
+fbnupywdcksxgvj
+bsqytkxnuocpwe
+
+lhpsuvgcmeqzj
+gjzphexlcvms
+hmljrocgwivtzkpase
+vcjlzuqdgpfhems
+evclzhbmpuxgysj
+
+zrawojsquknbihmepgxyv
+qefaowrgumldkbx
+qgekuxmcaflrbow
+
+xlza
+xzajl
+aryzlx
+xaclzj
+axzl
+
+cv
+cv
+cv
+vc
+cv
+
+brohlqgmzwiyvjkef
+nolmufhkwygjcevb
+
+mjayudk
+ci
+wcnsxo
+fc
+
+alvcxywzhperjqmdkn
+lwmesakjxcpdznvryhq
+kzdcprxevjhyamwlnq
+
+exr
+er
+
+nexlqvsawjbkfrhutcygzpdom
+qmbfjkgsvtiydelruaphzxwco
+zqjkumlhstafpvbxdweogrcyi
+
+l
+l
+l
+
+eoqxjms
+okqmefsxdhb
+
+b
+b
+b
+b
+
+mwfadliuhgskrejn
+berhwinfljmdausgk
+xzfjimunsltraqcwehg
+
+otf
+vhuap
+lkn
+d
+
+eabxzpfjuytwrg
+xreqgynzpiufbjatwl
+pbzuajwgcrtmyxfe
+
+dvwcr
+rdwvc
+
+qio
+qoi
+ioq
+oqi
+
+jbyi
+ojirb
+jiba
+bjig
+ijb
+
+dprgjzib
+jprqg
+xajpewhrg
+
+ehgvwcxydpal
+pdcnuawygebx
+
+mapdoqswbzenick
+cgqyxmwsvaeihpjzofb
+
+xqphsmjwblofntv
+mtejqivalgun
+
+xngvtoihcur
+oipgvtxcunrh
+
+dihof
+ifh
+fhiw
+hfiw
+hif
+
+ctrq
+txziwjcvl
+oanymhtd
+krexztpgus
+tvsi
+
+cqkvfn
+fvnkc
+npofwkxrcd
+ucfnk
+
+lnb
+bn
+bn
+nb
+
+pukncdrbeyvwsaqjohxgfltm
+qjepzvgwaxybrultfcsmkon
+
+nlczsygmdabuorweqjhxfitv
+nmuvojghteyaxibwldsqrzfc
+mihetjnswbyzdvufcogxaqrl
+iulxgqfoctnjhvrawbzemsdy
+exugdvclmqfzsojiwnbarhty
diff --git a/day6.ml b/day6.ml
new file mode 100644
index 0000000..ba17e07
--- /dev/null
+++ b/day6.ml
@@ -0,0 +1,89 @@
+module CharSet = Set_ext.Make(Char)
+
+let to_set str = String.to_seq str |> CharSet.of_seq
+
+let count_distinct str = to_set str |> CharSet.cardinal
+
+let main1 input =
+  Bracket.infile_chunks input ~join:"" ~chunk:count_distinct ~of_seq:List.of_seq
+  |> Misc.print_sum ~format:true
+
+let count_intersect strs =
+  match List.map to_set strs with
+  | []    -> failwith "empty list"
+  | s::ss -> List.fold_left CharSet.inter s ss |> CharSet.cardinal
+
+let main2 input =
+  Bracket.infile_chunks' input ~chunk:count_intersect ~of_seq:List.of_seq
+  |> Misc.print_sum ~format:true
+
+let main = Misc.main 6 [|main1; main2|]
+
+let%expect_test "main1" =
+  main1 "../../data/day6";
+  [%expect{|
+    26 + 8 + 24 + 21 + 22 + 13 + 6 + 8 + 14 + 20 + 16 + 15 + 8 + 24 + 7 + 5 + 6 +
+    18 + 7 + 25 + 24 + 6 + 13 + 13 + 4 + 24 + 9 + 6 + 8 + 6 + 18 + 14 + 16 + 3 +
+    26 + 11 + 22 + 12 + 1 + 13 + 13 + 12 + 9 + 17 + 7 + 25 + 14 + 21 + 6 + 9 +
+    8 + 1 + 16 + 23 + 2 + 19 + 17 + 25 + 8 + 14 + 8 + 11 + 15 + 2 + 21 + 17 +
+    24 + 6 + 11 + 12 + 20 + 8 + 25 + 16 + 12 + 17 + 4 + 24 + 4 + 21 + 16 + 7 +
+    14 + 2 + 19 + 2 + 26 + 8 + 1 + 3 + 7 + 8 + 14 + 21 + 19 + 17 + 12 + 20 + 17 +
+    16 + 12 + 5 + 2 + 22 + 13 + 21 + 20 + 22 + 16 + 14 + 5 + 23 + 9 + 5 + 6 +
+    23 + 23 + 12 + 15 + 2 + 18 + 16 + 25 + 9 + 14 + 2 + 17 + 16 + 26 + 24 + 8 +
+    19 + 17 + 10 + 12 + 5 + 14 + 4 + 6 + 3 + 11 + 16 + 1 + 26 + 3 + 20 + 3 + 12 +
+    18 + 12 + 26 + 10 + 9 + 16 + 11 + 12 + 3 + 1 + 21 + 8 + 18 + 5 + 19 + 18 +
+    1 + 10 + 10 + 11 + 12 + 13 + 13 + 7 + 8 + 8 + 15 + 12 + 7 + 4 + 13 + 13 +
+    17 + 3 + 15 + 20 + 4 + 10 + 2 + 9 + 21 + 4 + 15 + 11 + 17 + 5 + 1 + 6 + 12 +
+    20 + 18 + 4 + 2 + 22 + 6 + 4 + 7 + 10 + 23 + 23 + 8 + 6 + 7 + 8 + 1 + 6 +
+    12 + 9 + 9 + 24 + 8 + 7 + 9 + 20 + 16 + 18 + 26 + 26 + 6 + 13 + 19 + 11 +
+    23 + 9 + 26 + 12 + 22 + 16 + 20 + 4 + 3 + 5 + 21 + 4 + 21 + 8 + 25 + 26 +
+    20 + 20 + 3 + 12 + 25 + 10 + 21 + 15 + 5 + 15 + 14 + 12 + 26 + 20 + 20 + 5 +
+    15 + 20 + 20 + 26 + 24 + 22 + 13 + 15 + 13 + 10 + 21 + 11 + 20 + 11 + 2 +
+    18 + 2 + 18 + 15 + 19 + 17 + 26 + 7 + 16 + 18 + 5 + 3 + 23 + 17 + 3 + 19 +
+    11 + 25 + 2 + 20 + 22 + 3 + 9 + 8 + 5 + 18 + 24 + 7 + 8 + 6 + 26 + 4 + 13 +
+    26 + 26 + 8 + 23 + 17 + 25 + 20 + 24 + 22 + 10 + 5 + 24 + 10 + 15 + 1 + 21 +
+    20 + 9 + 19 + 4 + 10 + 20 + 10 + 21 + 2 + 14 + 22 + 20 + 9 + 7 + 16 + 25 +
+    12 + 22 + 19 + 10 + 12 + 5 + 6 + 23 + 3 + 11 + 23 + 25 + 2 + 5 + 11 + 22 +
+    3 + 3 + 22 + 15 + 3 + 19 + 20 + 2 + 5 + 24 + 15 + 1 + 23 + 20 + 24 + 6 + 8 +
+    8 + 15 + 9 + 15 + 10 + 6 + 15 + 19 + 11 + 11 + 13 + 1 + 15 + 18 + 6 + 20 +
+    13 + 23 + 12 + 16 + 16 + 9 + 26 + 12 + 7 + 19 + 6 + 26 + 9 + 3 + 11 + 8 +
+    11 + 7 + 22 + 6 + 8 + 4 + 9 + 2 + 11 + 16 + 18 + 18 + 26 + 10 + 24 + 9 + 26 +
+    23 + 8 + 21 + 19 + 7 + 21 + 2 + 9 + 21 + 13 + 11 + 12 + 22 + 5 + 6 + 25 +
+    16 + 8 + 9 + 18 + 22 + 3 + 7 + 12 + 22 + 25 + 19 + 9 + 18 + 4 + 16 + 23 + 8 +
+    6 + 10 + 22 + 20 + 22 + 25 + 25 + 8 + 2 + 20 + 15 + 19 + 3 + 26 + 1 + 12 +
+    1 + 22 + 12 + 20 + 5 + 3 + 8 + 14 + 15 + 22 + 20 + 12 + 6 + 24 + 13 + 3 +
+    25 + 24 =
+    6587 |}]
+
+let%expect_test "main2" =
+  main2 "../../data/day6";
+  [%expect{|
+    5 + 8 + 16 + 7 + 3 + 3 + 3 + 8 + 7 + 1 + 14 + 10 + 8 + 1 + 7 + 1 + 0 + 6 +
+    2 + 12 + 7 + 3 + 11 + 2 + 2 + 2 + 6 + 1 + 0 + 0 + 2 + 4 + 7 + 0 + 11 + 3 +
+    21 + 4 + 1 + 9 + 2 + 4 + 0 + 1 + 1 + 3 + 5 + 9 + 0 + 7 + 5 + 1 + 1 + 7 + 1 +
+    10 + 4 + 13 + 8 + 10 + 4 + 0 + 7 + 1 + 11 + 0 + 15 + 2 + 1 + 1 + 20 + 6 + 0 +
+    1 + 8 + 2 + 1 + 21 + 1 + 10 + 8 + 1 + 6 + 2 + 3 + 2 + 12 + 7 + 1 + 0 + 6 +
+    8 + 2 + 16 + 15 + 13 + 1 + 0 + 17 + 15 + 1 + 2 + 2 + 21 + 13 + 11 + 0 + 3 +
+    8 + 9 + 3 + 14 + 3 + 5 + 5 + 6 + 5 + 5 + 9 + 1 + 14 + 9 + 6 + 5 + 13 + 1 +
+    16 + 15 + 23 + 19 + 1 + 17 + 7 + 10 + 5 + 0 + 12 + 2 + 6 + 3 + 2 + 0 + 1 +
+    1 + 3 + 0 + 1 + 7 + 12 + 11 + 0 + 1 + 4 + 6 + 4 + 6 + 1 + 1 + 19 + 6 + 0 +
+    1 + 15 + 6 + 1 + 8 + 5 + 2 + 7 + 11 + 13 + 4 + 7 + 3 + 3 + 11 + 0 + 1 + 12 +
+    12 + 13 + 1 + 0 + 20 + 3 + 10 + 0 + 1 + 0 + 1 + 14 + 2 + 6 + 2 + 1 + 6 + 12 +
+    15 + 5 + 4 + 1 + 1 + 3 + 2 + 0 + 0 + 0 + 16 + 8 + 3 + 0 + 4 + 1 + 5 + 5 + 6 +
+    4 + 9 + 2 + 3 + 7 + 18 + 16 + 11 + 21 + 8 + 6 + 4 + 18 + 1 + 0 + 8 + 0 + 1 +
+    0 + 2 + 20 + 2 + 1 + 4 + 3 + 2 + 11 + 6 + 14 + 25 + 7 + 6 + 3 + 8 + 11 + 5 +
+    15 + 11 + 5 + 4 + 4 + 0 + 22 + 3 + 13 + 2 + 14 + 6 + 8 + 8 + 23 + 1 + 9 + 4 +
+    6 + 0 + 9 + 6 + 10 + 9 + 1 + 12 + 1 + 6 + 1 + 11 + 15 + 12 + 4 + 0 + 1 + 1 +
+    2 + 1 + 4 + 0 + 3 + 8 + 20 + 1 + 3 + 22 + 0 + 9 + 1 + 3 + 1 + 5 + 4 + 8 + 4 +
+    5 + 1 + 2 + 5 + 18 + 0 + 17 + 3 + 2 + 16 + 19 + 7 + 7 + 5 + 18 + 1 + 14 + 1 +
+    19 + 18 + 7 + 10 + 2 + 2 + 3 + 9 + 2 + 2 + 9 + 7 + 20 + 0 + 6 + 12 + 5 + 11 +
+    7 + 2 + 10 + 8 + 3 + 5 + 22 + 2 + 6 + 10 + 14 + 0 + 1 + 4 + 3 + 3 + 1 + 10 +
+    5 + 3 + 9 + 14 + 0 + 0 + 23 + 10 + 1 + 14 + 5 + 21 + 3 + 8 + 4 + 9 + 5 + 11 +
+    8 + 3 + 13 + 0 + 8 + 5 + 3 + 1 + 15 + 8 + 2 + 5 + 13 + 10 + 8 + 12 + 13 + 6 +
+    6 + 7 + 7 + 8 + 2 + 14 + 6 + 0 + 9 + 4 + 8 + 4 + 0 + 2 + 7 + 3 + 2 + 2 + 2 +
+    4 + 18 + 15 + 24 + 5 + 6 + 4 + 26 + 14 + 3 + 14 + 14 + 3 + 3 + 2 + 8 + 6 +
+    12 + 0 + 3 + 0 + 3 + 6 + 2 + 13 + 1 + 3 + 1 + 22 + 0 + 0 + 4 + 17 + 10 + 13 +
+    3 + 9 + 4 + 5 + 9 + 4 + 0 + 4 + 20 + 20 + 10 + 11 + 12 + 4 + 2 + 13 + 0 +
+    18 + 2 + 24 + 1 + 6 + 1 + 14 + 0 + 14 + 5 + 3 + 3 + 4 + 9 + 12 + 7 + 11 + 3 +
+    1 + 4 + 2 + 22 + 24 =
+    3235 |}]
diff --git a/misc.ml b/misc.ml
index 093a1ef..78fdb6e 100644
--- a/misc.ml
+++ b/misc.ml
@@ -26,16 +26,23 @@ let%test _ = fold_list add  [1;2;3;4] = 10
 let%test _ = fold_list mult [1;2;3;4] = 24
 
 
-let print_fold mon xs =
+let print_fold ?(format=false) mon xs =
   let res = List.fold_left mon.op mon.id xs in
   let rec go fmt = function
     | []    -> Format.fprintf fmt "%a" mon.pp mon.id
     | [x]   -> Format.fprintf fmt "%a" mon.pp x
-    | x::xs -> Format.fprintf fmt "%a %s %a" mon.pp x mon.op_name go xs in
-  Format.printf "%a = %a\n" go xs mon.pp res
+    | x::xs ->
+        let f =
+          if format then Format.fprintf fmt "%a %s@ %a"
+          else Format.fprintf fmt "%a %s %a" in
+        f mon.pp x mon.op_name go xs in
+  let f =
+    if format then Format.printf "%a =@ %a\n"
+    else Format.printf "%a = %a\n" in
+  f go xs mon.pp res
 
-let print_prod = print_fold mult
-let print_sum  = print_fold add
+let print_prod ?format = print_fold ?format mult
+let print_sum  ?format = print_fold ?format add
 
 let%expect_test _ =
   print_prod [];
diff --git a/misc.mli b/misc.mli
index cb59edb..e49faca 100644
--- a/misc.mli
+++ b/misc.mli
@@ -14,6 +14,6 @@ val fold_list: 'a monoid -> 'a list -> 'a
 val mult: int monoid
 val add: int monoid
 
-val print_fold: 'a monoid -> 'a list -> unit
-val print_prod: int list -> unit
-val print_sum:  int list -> unit
+val print_fold: ?format:bool -> 'a monoid -> 'a list -> unit
+val print_prod: ?format:bool -> int list -> unit
+val print_sum:  ?format:bool -> int list -> unit
diff --git a/seq.ml b/seq.ml
index 76f1e47..03995b0 100644
--- a/seq.ml
+++ b/seq.ml
@@ -57,7 +57,7 @@ let chunks p =
     | Span (lst, seq) -> Some (lst, drop_while p seq))
 
 let line_chunks' = chunks (fun s -> s = "")
-let line_chunks seq = map (String.concat " ") (line_chunks' seq)
+let line_chunks ?(join=" ") seq = map (String.concat join) (line_chunks' seq)
 
 let%test_module _ = (module struct
   let lc lst = List.(of_seq (line_chunks (to_seq lst)))
diff --git a/seq.mli b/seq.mli
index 736120e..a9f0d59 100644
--- a/seq.mli
+++ b/seq.mli
@@ -14,4 +14,4 @@ val drop_while: ('a -> bool) -> 'a t -> 'a t
 val chunks: ('a -> bool) -> 'a t -> 'a list t
 
 val line_chunks': string t -> string list t
-val line_chunks: string t -> string t
+val line_chunks: ?join:string -> string t -> string t