diff --git a/2025/day11/input b/2025/day11/input
new file mode 100644
index 0000000..c1adfe6
--- /dev/null
+++ b/2025/day11/input
@@ -0,0 +1,574 @@
+fxp: udl vii hgb qmy
+ixc: cje lra jhu
+sgn: apv vbc
+wua: knq
+fnr: csd awl vvj fyx cvi xhb mvn guw wid vbp uvk krt oil izj zlh gwv
+krt: grp cml vxt
+hwj: laq jlg
+rus: out
+oag: wrc gpp
+uos: zqg aiu gdx
+xpu: qpb zqg gdx aiu
+mdb: fnr mwu ozd
+yrt: jlg ifs laq
+eao: txi jmk xee sta knq
+qcj: ivn mwb nrx lgx
+wks: fyy lyd
+xso: rqn flj fak
+ucp: wpn mpy
+zcf: knq sta xee jmk
+sdr: vfy gsc wfb
+ggn: brb ylm kdl rnk
+tky: wcx ytk hbp xjh dne
+kzl: sft sof utn
+epc: uhn cqf xwv
+srh: shh mei
+uqe: sft
+htw: hmf aia wsm
+wid: qwo
+daz: yvs
+bdl: ipm kkp
+xay: mpi
+bsb: epc jpb cqs ixc cur ril ybr
+mwb: out
+cxr: yvs
+ruf: jax uvl ctm
+vtp: rbo
+tqs: kdl pje ylm brb
+thb: out
+ljy: ael tqw
+tkl: ssx yds
+ozd: itv csd vvj fyx awl xhb mvn guw vbp hzn yft mfv izj oil uvk cui krt myo fqn gwv zlh
+uhn: lzx dac iqf
+zad: wvh tmc ece
+qlf: gce sgn fni
+kcf: dka pvw uzw
+uat: bda mkd
+aai: gtk gkf cuk qcj
+mfv: cml
+qlv: wdr sbi ihm nww jkx bud qxb
+paz: kbq osk
+rys: iwh
+gdx: out
+hco: cuk gkf
+gte: wks fft
+zrw: iur mei shh
+izj: elj wrh vnz uss
+lur: jpb zib zwl uzn epc nta cur cqs ybr tkl sle
+hgu: jmk xee
+okf: ypu gye qzd
+mli: dir mzw
+shh: rjp
+nhj: ael tqw
+pbm: fxp dfl
+vnz: che
+vim: bmu
+puz: dcl ofd
+zrg: ihy
+scj: ysr knu
+pjc: uvl jax bvs
+tbn: uat lkd fdg
+rcp: okf
+min: out
+poc: rta yvs rbo
+kde: bcz
+wct: bvs jax uvl
+wvh: brg
+wrh: frd kbe ihy
+fak: jwl lzu dni
+zaq: jlg ifs laq ppm
+yun: kde kob qmz uxn
+boa: yql brg fbt sgu
+izk: czt
+xyj: out
+xhk: ril cur yun pmu nta epc uzn zwl rxn sle tkl puz ixc cqs nqo jpb zzk
+yql: mjy cfo bpj vqp
+dcl: nbq
+ogv: utn sof pld
+rtp: gpp gmb eka
+nki: jmk xee knq
+agn: jly alh ola zcf
+vrp: hnw
+lts: yql fbt sgu
+myo: rhq kvi
+jpb: dcl xuk
+dju: vrt ozd fnr you mwu
+hnw: hmf
+rhq: ehc
+dij: knq sta xee txi
+awl: vxt
+knu: bsb lur igu
+dfo: pab
+ewm: sgn fni gce
+fed: osk
+nwy: ppm laq qgn
+wby: you mwu fnr ozd
+dir: jmn gpu
+mjy: wfb iyi vfy
+fcj: zkn hgq szd
+mzo: out
+lzl: xhk
+czt: xcu xvu
+tyq: gsc wfb kjq iyi
+tda: rbo
+ltv: srf vim mli slg
+iwh: qpo
+hnn: bsb fpb lur
+fan: sgu
+vqp: zow rqn fak flj wke
+ltm: pvm xmq
+cyc: dfl fxp
+kvi: gwp jnw
+srd: ipm jrk
+lkv: fnr vrt
+shb: hxf thb rus
+xuk: zxj
+ifs: ryr gep wck lcp fwn gdh foj
+ynz: uji
+igh: sta jmk
+fyx: krd
+gkf: ivn mwb axi
+bcz: ftm rdm wby lkv
+qeg: jlg qgn ifs ppm
+goq: icv
+qmy: out
+wxl: igh heh hvs
+kbe: dzp ybw
+hxf: out
+tqw: rdn nac
+bmu: jmn gkl xfg
+cqf: lzx
+phn: rbi fjm
+ykt: sgu fbt brg
+zqg: out
+ain: mpj
+esz: jmk txi
+bpj: rqn zow flj wke fak
+qaj: gtk gkf cuk qcj
+kul: ckh
+rss: dka nwy
+gaq: ifs laq jlg
+ehc: hco qaj qup
+saf: mwu you fnr vrt
+mub: bee
+tns: lyd fyy bqw
+ssx: utb nel thp hhu wbs
+mwd: qeg gpo
+lgx: out
+lyr: ozd
+knq: qlf tnt bhv aeo ljy dmr
+php: sgu
+qmz: fer bcz
+oab: lup
+sof: ikt
+lte: ytk hbp xjh dne wcx
+hvs: xee txi knq
+bnw: yhu qhx
+jnw: aai hco qup nxs
+uge: bqw fyy
+cml: sid txz qgh
+sle: uwp jhu lra ltm
+uoi: yql sgu
+tcu: eao hgu
+aaj: laq ppm
+bqy: you
+gye: qpo
+csx: you mwu fnr vrt
+uut: dne xjh wcx
+tat: kul jxm dxd shb wtu
+sbi: yvn mub
+uss: suv ihy kbe
+def: wrc eka gpp
+rso: out
+dmr: oab kbr jaa
+jhu: xmq
+qxb: mub sfu fhq yvn
+nww: htw
+szd: zfx
+gpp: qvv min rso iey
+sft: fzl hnn ikt
+fwn: mei iur
+giz: txi sta jmk
+you: hzn izj oil krt wid awl vbp csd
+yvs: fpb lur xhk bsb
+mci: jrk ipm kkp
+nqo: uwp jhu cje
+alh: jmk xee sta txi
+ejz: fjm rbi fim
+jnd: wua esz
+igu: nta pmu yun cur ril ybr rxn zwl uzn fnn cqs ixc puz sle zzk jpb nqo zib
+yft: tky kcj
+vxt: sid
+dni: hvs heh mpi
+jwy: wtu
+ypu: yrt
+rqn: lzu dni
+yfw: bag puu yba
+vgx: amv gte qwd hpw
+hgb: out
+gwp: nxs qaj
+obo: fbt
+yhu: xkn jai boa
+phi: bqy ftm
+cmi: xyj
+mvn: ruf btp
+utn: ikt
+mkd: zcf giz alh
+eff: zow rqn wke flj
+dml: yql brg sgu fbt
+ivn: out
+fft: fyy lyd
+vbp: vnz
+cuk: ivn lgx axi nrx
+brb: lts bcq xsx fan
+ckh: out
+cui: zrg elj wrh vnz uss
+ybw: pxr
+sfu: bee ynz
+aov: gyl xyj
+yxq: jsh smb qhx
+hgq: xvu
+yba: pab xbk bvq
+ser: mzo vii hgb qmy
+xfg: txi xee
+iey: out
+vhi: jaa kbr evt ndc
+kcj: hbp
+qmf: zfx
+tum: sgu brg yql
+sva: her yfw anr
+ctm: cyc
+sta: ewm izk bhv tnt vhi hkq ljy waa aeo ofz xhd fcj gwo qlf nhj
+jai: fbt sgu
+iyj: dka kez nwy
+ofd: tlb
+qff: rcp osk
+wbs: fnr you mwu vrt ozd
+ulj: hrd tcu uqb
+uvk: vxt grp qgy
+txz: irm jwy fmr
+yco: out
+hlo: fxp ser
+gsc: ldf yqe ulj
+vpo: zxj tlb
+jgf: laq
+hns: uoi tmc ece
+cvi: gpt otp sva
+cur: kob kde qmz
+lre: ipm
+ryr: wpn fdl
+wrc: iey yco
+ftq: fvb kbp scb oap cvl
+qwd: tns wks uge
+laq: ryr nhf srh zrw bvv xje gep phn ejz ucp vgx foj gdh tph
+fyy: vin obo dml php tum
+iyi: yqe ldf axk
+wck: mei iur
+lzu: mpi
+btp: uvl ctm bvs jax
+zib: jhu lra cje ltm uwp
+dac: lyr csx saf rmg vns
+pje: lts ykt bcq
+awp: oap kbp
+iqf: lyr vns
+fac: qgn
+iiu: lre
+gmb: min rso
+pxk: wsm
+icv: jlg ifs laq
+tnt: oab ndc kbr evt
+guw: otp qwo
+rjp: fbt sgu
+iqh: srf vim mli slg
+xje: mpy
+cmt: amv gte
+kob: bcz fer
+fzl: igu fpb
+bud: rss fxl
+lup: fvb cvl
+bpc: jsh smb yhu
+jui: fnr mwu you vrt ozd
+wmr: tmc uoi wvh
+ulo: yql brg sgu
+quz: hns avo euq zad
+avo: wvh uoi tmc
+wtu: rus thb hxf ckh
+jsh: xkn ulo boa ahv
+bbz: mwd imq
+hpw: fft tns uge
+nbq: gcg jui zqy
+cel: fxp dfl
+jrk: lsu nki wgx
+qzd: acm yrt qpo
+xcu: ain
+qxl: lur igu bsb
+pmu: xuk dcl ofd
+ahv: fbt brg
+gtk: lgx nrx
+vrt: yft izj uvk cui mfv oil myo hzn gwv zlh fqn guw vbp wid xhb mvn csd itv cvi fyx awl
+gcg: vrt
+ppm: bvv zrw vis dcr wck ryr gdh tph ucp ejz uuh gep
+nel: ozd fnr
+udl: out
+gkl: knq txi jmk xee
+vvj: btp pjc wct
+adp: cxr vtp daz poc
+zxj: jui gcg zqy
+dka: ifs laq qgn jlg
+bhl: xpu uos
+mzw: jmn xfg
+ycr: qmf hgq szd czt
+zfx: dbo ain scj
+jax: pbm bxg cel cyc hlo
+yqe: jnd uqb hrd
+lyd: dml php vin obo
+euq: uoi ece
+hzn: wct
+gwv: uut tky lte
+wgx: sta xee knq
+xhd: phh ael
+axk: tcu uqb
+ece: sgu fbt
+waa: jaa
+jaa: ftq lup awp
+cje: xmq pvm
+lln: bbz qff dkw paz htf fhv vrp jkx ihm bud jef eej
+bvs: pbm cel
+zow: xay wxl
+pvm: fnr you vrt ozd
+dbo: knu
+vbc: pld
+xpp: iwh qzd gye
+gep: fdl
+qqj: xhk bsb lur fpb
+wpo: fdg
+qgy: sid qgh
+dne: oag def
+oap: igu lur bsb xhk
+bee: oxm uji tpb jgf
+dxd: rus thb
+mjp: jgf mkp
+ytc: brg yql sgu fbt
+zlh: krd kvi rhq
+wcx: def oag rtp
+svr: qlv lln qwc
+ola: sta xee jmk txi
+qwc: jkx ihm nww sbi bud fed jef eej bbz qff nfj paz fhv vrp wdr
+gce: kzl ogv
+uxn: phi bcz
+vnd: fbt brg
+xee: uni hkq ljy qlf aeo
+zaz: cmi
+gpt: yfw
+dkm: gaq fac aaj zaq
+kjq: sgy
+oba: qgn jlg
+slg: dir
+fvb: xhk bsb igu lur
+csd: gpt otp qwo
+kkp: dij pbf
+osk: xpp rys
+hmf: pde luh dkm
+uwn: lkd
+crd: ikt hnn fzl
+acm: jlg qgn laq
+utb: fnr mwu you
+lcp: rbi
+mby: out
+fbt: tbn iiu uxu sdr wyl uwn xao ltv wpo mjy xso
+fhq: ynz mjp
+qhx: ahv boa ulo jai
+wpn: bpo
+xbk: mby
+axi: out
+rbi: yxq bnw
+dcr: fjm
+nxs: gkf cuk qcj
+rxn: uwp jhu lra ltm
+kez: ifs
+ikt: xhk bsb igu fpb
+nhf: pje
+lsu: xee sta jmk
+ejp: oba aaj gaq
+tph: rnk brb
+bpo: wmr euq
+ybr: uhn cqf
+pde: gaq
+kbp: xhk bsb
+fhv: pxk htw
+lkd: bda mkd agn bhh
+fmr: shb wtu kul
+ftm: ozd vrt
+aeo: szd qmf hgq
+dhu: ogv apv vbc kzl
+irh: mpj ysr qxl
+thp: you ozd vrt
+bda: alh jly ola zcf giz
+uzw: laq ifs qgn
+scb: bsb
+aeb: wbs hhu nel utb
+vin: brg
+rnk: fan
+sid: jwy fmr irm
+uxu: slg mli vim srf
+anr: yba puu zaz
+kbq: rys
+jwl: igh
+vis: amv hpw gte qwd
+fer: lkv wby rdm bqy ftm
+kwv: ola jly zcf
+nac: lur
+xvu: phc irh
+luh: aaj zaq oba gaq
+bcq: fbt sgu brg yql
+puu: bvq xbk
+mei: rjp ytc vnd
+lyf: igu xhk bsb
+tmc: fbt
+suv: rzo dzp qig bhl
+qwo: anr
+uuh: iur
+dfl: mzo vii
+hrd: esz wua
+eka: min rso qvv yco
+qpb: out
+zqy: you mwu
+evt: lup
+bxg: dfl fxp
+uni: oab kbr evt jaa
+uwp: xmq dju
+rdm: ozd vrt you fnr
+gwo: poc
+dto: bsb xhk lur fpb
+ofz: dhu fni sgn
+fjm: bpc
+wsm: pde luh ejp
+tmb: amv qwd
+kdl: bcq ykt lts
+jxm: ckh hxf
+dyl: euq avo wmr hns
+pxr: zqg
+xsx: yql brg
+wdr: rss fxl kcf
+frd: rzo qig dzp bhl
+tlb: zqy mdb
+yvn: ynz mjp
+bvv: fim
+xjh: oag def
+jmk: vhi bhv tnt izk ewm adp nhj qlf gwo fcj xhd ofz aeo ycr ljy hkq
+smb: ahv xkn ulo
+hbp: def rtp
+fdl: quz bpo
+flj: xay wxl
+mkp: qgn jlg
+fdg: mkd agn bda kwv bhh
+mpy: bpo quz dyl
+fim: yxq bnw bpc
+mwu: xhb yft myo cui gwv mvn fqn fyx vbp wid
+yds: hhu nel
+her: dfo yba puu bag
+ipm: nki wgx lsu pbf
+wfb: ulj axk ldf
+bvq: xyj
+hhu: ozd you fnr
+vfy: ulj yqe ldf axk
+pld: qqj fzl
+zkn: xvu zfx xcu
+rbo: fpb lur
+zzk: yds aeb
+rdn: bsb igu fpb
+ril: qmz uxn kde kob
+foj: fdl
+xhb: krd kvi
+htf: osk rcp
+nrx: out
+zwl: xwv uhn cqf
+gyl: out
+dkw: rcp osk
+sgu: wyl iiu vqp bpj sdr tyq tbn cfo eff wpo xso xao ltv
+pbf: sta
+ytk: oag
+irm: shb kul
+brg: wpo iqh tyq tbn uwn
+dzp: xpu uos
+ufe: utb nel hhu
+gpo: jlg
+ihy: bhl rzo dzp qig
+jlg: srh tqs bvv tmb dcr
+qgh: jwy fmr tat irm
+aiu: out
+itv: grp qgy
+cqs: yds ufe ssx
+mpj: igu xhk
+pvw: ppm laq
+mpi: xee knq
+pab: gyl
+jef: rss kcf iyj
+qig: pxr xpu
+lra: pvm
+che: rzo qig dzp ybw
+xao: rqn fak wke
+nta: vpo xuk
+rta: lur igu bsb
+qvv: out
+fpb: puz cqs ixc fnn tkl nqo jpb zzk zib yun cur pmu nta ybr ril uzn zwl
+imq: hwj qeg gpo
+jkx: fhq mub sfu
+ael: lzl dto
+wyl: srd bdl mci
+hkq: zkn czt
+apv: utn crd sof pld
+kbr: ftq
+xwv: iqf lzx
+cfo: lre bdl srd
+ysr: fpb xhk bsb
+aia: dkm ejp
+ndc: awp lup ftq
+bhh: ola
+bhv: poc daz vtp tda cxr
+uqb: hgu
+xkn: yql
+eej: imq
+ihm: htw pxk
+phh: rdn lyf nac
+cvl: fpb igu lur xhk
+rzo: uos
+uzn: kde
+jly: jmk sta xee knq
+otp: her
+vii: out
+fni: ogv uqe kzl
+phc: ysr
+srf: bmu mzw
+fnn: xwv
+rmg: you
+heh: knq jmk xee txi
+elj: frd kbe che suv
+fxl: dka kez pvw uzw
+sgy: uqb
+vns: vrt fnr
+gdh: hpw
+bag: pab aov xbk cmi
+bqw: dml tum php
+txi: aeo dmr adp waa nhj uni
+krd: gwp
+wke: dni wxl jwl
+ldf: uqb tcu hrd
+jmn: knq xee jmk
+ylm: fan bcq lts
+qpo: ppm laq qgn jlg
+qgn: ucp ejz phn cmt lcp uuh xje tqs gep foj gdh tph nhf fwn dcr wck ryr bvv tmb zrw srh vis ggn
+tpb: ifs laq
+uvl: hlo cel bxg pbm
+iur: rjp vnd ytc
+oil: uut lte
+oxm: ppm laq qgn jlg
+grp: qgh sid
+lzx: vns csx saf
+uji: qgn jlg ppm laq
+amv: wks uge tns
+qup: qcj
+xmq: mwu you
+fqn: sva
+gpu: sta xee jmk txi
+nfj: mwd goq
diff --git a/2025/day11/main.go b/2025/day11/main.go
new file mode 100644
index 0000000..7acc632
--- /dev/null
+++ b/2025/day11/main.go
@@ -0,0 +1,101 @@
+package main
+
+import (
+	"fmt"
+	"slices"
+	"strings"
+
+	h "git.bullercodeworks.com/brian/adventofcode/helpers"
+)
+
+func main() {
+	inp := h.StdinToStringSlice()
+	part1(inp)
+	fmt.Println()
+	part2(inp)
+}
+
+func part1(inp []string) {
+	m := parseInput(inp)
+	cache = make(map[string]int)
+	fmt.Println("# Part 1")
+	fmt.Println(findPaths("you", "out", m))
+}
+
+func part2(inp []string) {
+	m := parseInput(inp)
+	fmt.Println("# Part 2")
+	fmt.Println(findPaths2(m, m["svr"], false, false, map[track]int{}))
+}
+
+type track struct {
+	node     string
+	fft, dac bool
+}
+
+func parseInput(inp []string) map[string][]string {
+	ret := make(map[string][]string)
+	for i := range inp {
+		pts := strings.Fields(inp[i])
+		st := pts[0][:len(pts[0])-1]
+		ret[st] = pts[1:]
+	}
+	return ret
+}
+
+var cache map[string]int
+
+func findPaths(start, end string, m map[string][]string) int {
+	if v, ok := cache[start]; ok {
+		return v
+	}
+	var ret int
+	v := m[start]
+	for i := range v {
+		if v[i] == end {
+			ret++
+		} else {
+			ret += findPaths(v[i], end, m)
+		}
+	}
+	cache[start] = ret
+	return ret
+}
+
+func findPaths2(m map[string][]string, vals []string, fft, dac bool, cache map[track]int) int {
+	var ret int
+	if slices.Contains(vals, "out") {
+		if fft && dac {
+			return 1
+		}
+		return 0
+	}
+
+	for _, i := range vals {
+		hfft, hdac := fft, dac
+		t := track{
+			node: i,
+			fft:  hfft,
+			dac:  hdac,
+		}
+		if v, ok := cache[t]; ok {
+			ret += v
+			continue
+		}
+
+		switch i {
+		case "fft":
+			hfft = true
+		case "dac":
+			hdac = true
+		}
+		t = track{
+			node: i,
+			fft:  hfft,
+			dac:  hdac,
+		}
+		cache[t] = findPaths2(m, m[i], hfft, hdac, cache)
+		ret += cache[t]
+	}
+	return ret
+}
diff --git a/2025/day11/problem b/2025/day11/problem
new file mode 100644
index 0000000..2ea7f87
--- /dev/null
+++ b/2025/day11/problem
@@ -0,0 +1,141 @@
+[1]Advent of Code
+   br0xen [7](AoC++) 22*
+
+--- Day 11: Reactor ---
+
+   You hear some loud beeping coming from a hatch in the floor of the
+   factory, so you decide to check it out. Inside, you find several large
+   electrical conduits and a ladder.
+
+   Climbing down the ladder, you discover the source of the beeping: a large,
+   toroidal reactor which powers the factory above. Some Elves here are
+   hurriedly running between the reactor and a nearby server rack, apparently
+   trying to fix something.
+
+   One of the Elves notices you and rushes over. "It's a good thing you're
+   here! We just installed a new server rack, but we aren't having any luck
+   getting the reactor to communicate with it!" You glance around the room
+   and see a tangle of cables and devices running from the server rack to the
+   reactor. She rushes off, returning a moment later with a list of the
+   devices and their outputs (your puzzle input).
+
+   For example:
+
+ aaa: you hhh
+ you: bbb ccc
+ bbb: ddd eee
+ ccc: ddd eee fff
+ ddd: ggg
+ eee: out
+ fff: out
+ ggg: out
+ hhh: ccc fff iii
+ iii: out
+
+   Each line gives the name of a device followed by a list of the devices to
+   which its outputs are attached. So, bbb: ddd eee means that device bbb has
+   two outputs, one leading to device ddd and the other leading to device
+   eee.
+
+   The Elves are pretty sure that the issue isn't due to any specific device,
+   but rather that the issue is triggered by data following some specific
+   path through the devices. Data only ever flows from a device through its
+   outputs; it can't flow backwards.
+
+   After dividing up the work, the Elves would like you to focus on the
+   devices starting with the one next to you (an Elf hastily attaches a label
+   which just says you) and ending with the main output to the reactor (which
+   is the device with the label out).
+
+   To help the Elves figure out which path is causing the issue, they need
+   you to find every path from you to out.
+
+   In this example, these are all of the paths from you to out:
+
+     • Data could take the connection from you to bbb, then from bbb to ddd,
+       then from ddd to ggg, then from ggg to out.
+     • Data could take the connection to bbb, then to eee, then to out.
+     • Data could go to ccc, then ddd, then ggg, then out.
+     • Data could go to ccc, then eee, then out.
+     • Data could go to ccc, then fff, then out.
+
+   In total, there are 5 different paths leading from you to out.
+
+   How many different paths lead from you to out?
+
+   Your puzzle answer was 585.
+
+--- Part Two ---
+
+   Thanks in part to your analysis, the Elves have figured out a little bit
+   about the issue. They now know that the problematic data path passes
+   through both dac (a [16]digital-to-analog converter) and fft (a device
+   which performs a [17]fast Fourier transform).
+
+   They're still not sure which specific path is the problem, and so they now
+   need you to find every path from svr (the server rack) to out. However,
+   the paths you find must all also visit both dac and fft (in any order).
+
+   For example:
+
+ svr: aaa bbb
+ aaa: fft
+ fft: ccc
+ bbb: tty
+ tty: ccc
+ ccc: ddd eee
+ ddd: hub
+ hub: fff
+ eee: dac
+ dac: fff
+ fff: ggg hhh
+ ggg: out
+ hhh: out
+
+   This new list of devices contains many paths from svr to out:
+
+ svr,aaa,fft,ccc,ddd,hub,fff,ggg,out
+ svr,aaa,fft,ccc,ddd,hub,fff,hhh,out
+ svr,aaa,fft,ccc,eee,dac,fff,ggg,out
+ svr,aaa,fft,ccc,eee,dac,fff,hhh,out
+ svr,bbb,tty,ccc,ddd,hub,fff,ggg,out
+ svr,bbb,tty,ccc,ddd,hub,fff,hhh,out
+ svr,bbb,tty,ccc,eee,dac,fff,ggg,out
+ svr,bbb,tty,ccc,eee,dac,fff,hhh,out
+
+   However, only 2 paths from svr to out visit both dac and fft.
+
+   Find all of the paths that lead from svr to out. How many of those paths
+   visit both dac and fft?
+
+   Your puzzle answer was 349322478796032.
+
+   Both parts of this puzzle are complete! They provide two gold stars: **
+
+   At this point, you should [18]return to your Advent calendar and try
+   another puzzle.
+
+   If you still want to see it, you can [19]get your puzzle input.
+
+References
+
+   Visible links
+   1. https://adventofcode.com/
+   2. https://adventofcode.com/2025/about
+   3. https://adventofcode.com/2025/events
+   4. https://adventofcode.com/2025/shop
+   5. https://adventofcode.com/2025/settings
+   6. https://adventofcode.com/2025/auth/logout
+   7. Advent of Code Supporter
+	https://adventofcode.com/2025/support
+   8. https://adventofcode.com/2025
+   9. https://adventofcode.com/2025
+  10. https://adventofcode.com/2025/support
+  11. https://adventofcode.com/2025/sponsors
+  12. https://adventofcode.com/2025/leaderboard/private
+  13. https://adventofcode.com/2025/stats
+  14. https://adventofcode.com/2025/sponsors
+  16. https://en.wikipedia.org/wiki/Digital-to-analog_converter
+  17. https://en.wikipedia.org/wiki/Fast_Fourier_transform
+  18. https://adventofcode.com/2025
+  19. https://adventofcode.com/2025/day/11/input
diff --git a/2025/day11/testinput b/2025/day11/testinput
new file mode 100644
index 0000000..01e5b43
--- /dev/null
+++ b/2025/day11/testinput
@@ -0,0 +1,10 @@
+aaa: you hhh
+you: bbb ccc
+bbb: ddd eee
+ccc: ddd eee fff
+ddd: ggg
+eee: out
+fff: out
+ggg: out
+hhh: ccc fff iii
+iii: out
diff --git a/2025/day11/testinput2 b/2025/day11/testinput2
new file mode 100644
index 0000000..d787665
--- /dev/null
+++ b/2025/day11/testinput2
@@ -0,0 +1,13 @@
+svr: aaa bbb
+aaa: fft
+fft: ccc
+bbb: tty
+tty: ccc
+ccc: ddd eee
+ddd: hub
+hub: fff
+eee: dac
+dac: fff
+fff: ggg hhh
+ggg: out
+hhh: out