Sat

19

Jul

2014

An excellent hand-made Alcazar

This puzzle was made by Reddit user edderiofer, who was also one of the most active beta-testers of the Alcazar Android app.

 

With only 4 exits and lots of walls, it doesn't look so hard at first glance. However, you will soon realize that it's one of the most surprising and difficult Alcazars to date.

 

How will you approach it? If you find a simple and elegant way to solve it, please share it in the comments below. However, when you give a clue, make sure to encode it using this tool:

http://www.rot13.com/

 

Click here for a full screen version of the puzzle.

 

Have fun!

Coordinates

 

An easy way to talk about different techniques is to use chessboard notation: column are called A,B,C... (left to right) and rows are called 1,2,3... (bottom to top).

 

Example:

- C3D4 has a wall

- The room A1:D4 has 4 exits 


Write a comment

Comments: 17
  • #1

    Jérôme Morin-Drouin (Saturday, 19 July 2014 13:07)

    Here is an example of a "hidden clue". Use rot13.com to read it:

    Pbatenghyngvbaf sbe qrpbqvat guvf.

  • #2

    Daniel (Saturday, 19 July 2014 14:04)

    Gur prageny pbyhza nyybjf sbe sbhe cbffvoyr ynlbhgf: cnff sebz bar fvqr gb gur bgure ng gur gbc, cnff sebz bar fvqr gb gur bgure ng gur obggbz, fgneg ba yrsg, tb gb gur evtug fvqr naq erghea, fgneg ba evtug, tb gb gur yrsg fvqr naq erghea. V unccrarq gb pbeerpgyl thrff juvpu bar vg vf, ohg vg'f cbffvoyr gb ehyr bhg gur bgure guerr ernyyl dhvpxyl ba gur evtug unaq fvqr (gur gbc evtug naq obggbz evtug pbearef qba'g nyybj sbe zhpu inevrgl). Lbh zvtug frr guvf nf n ovg bs n purng nf vg vaibyirf thrffvat naq onpx genpxvat.

  • #3

    Steve (Saturday, 19 July 2014 14:50)

    V guvax gur guvat gung znxrf guvf yriry fgenvtug sbejneq vf gung gurer'f bayl 4 rkvgf, juvpu tvir bayl 6 cbffvoyr rkvg pbasvthengvbaf; bapr V ernyvfrq gung V fgnegrq gb ybbx ng gur yriry sbe nflzzrgevrf juvpu jbhyq tvir njnl juvpu bs gurfr 6 pbasvthengvbaf zvtug or n cbffvovyvgl, tvira gur yriry vf rssrpgviryl fcyvg qbja gur zvqqyr lbh pna pbafvqre rnpu fvqr va vfbyngvba naq whfg ybbx ng gur pbaarpgvivgl gung jbhyq unir gb rkvfg orgjrra gur fvqrf sbe gur chmmyr gb or pbzcyrgnoyr; V gbbx gur evtug unaq fvqr svefg naq dhvpxyl ernyvfrq gung vg'f vzcbffvoyr sbe gur rkvgf ba gur evtugunaq fvqr gb or hfrq, nf gurer'f ab pbasvthengvba bs yvarf juvpu nyybjf bar bs gubfr rkvgf gb or gnxra naq gur arprffnel pbaarpgvivgl gb gur erfg bs gur yriry; bapr V unq gur evtugunaq fvqr bs gur chmmyr pbzcyrgr, gur yrsg jnf snveyl fgenvtug sbejneq. Qrfcvgr fbyivat vg snveyl fjvsgyl guvf yriry jnf ernyyl vagrerfgvat, gurer jnf n qrsvavgr srryvat bs n qvssrerag qrfvta nccebnpu gnxra gb guvf yriry, V rawblrq vg :)

  • #4

    Icarox (Saturday, 19 July 2014 15:04)

    Zl fbyhgvba hfrf gur gbc yrsg naq obggbz yrsg ragenaprf.

    Fbzrguvat V abgvprq vzzrqvngryl jnf gung gur funcr bs gur cynlvat svryq jnf pbzcyrgryl fdhner, naq nyfb gung gur gjb znva uvtujnlf va gur zvqqyr qvqa'g pbaarpg.
    V fgnegrq dhrfgvbavat jul gurfr gjb znva yvarf jrera'g pbaarpgrq, naq jul gubfr jnyyf jrer gurer. V gubhtug gb zlfrys gung qhr gb gur flzzrgel bs gur cynlvat svryq, gur fbyhgvba jbhyq eryl ba jurer naq ubj gur yvarf jbhyq pbaarpg tbvat guebhtu gurfr zvqqyr ynarf.

    Nyfb orpnhfr gur svryq bayl unf 4 qvssrerag rkvgf. Gur nzbhag bs cbffvoyr fbyhgvbaf jrer qvpgngrq ol ubj gurl jbhyq eryngr jvgu gur zvqqyr ynar. Jbhyq gurl pbaarpg va gur zvqqyr? Be jbhyq gurl qb n n puvpxra enpr naq ghea onpx ng gur ynfg frpbaq?
    Gurer ner bayl 6 cbffvoyr ragenaprf-rkvgf pbzobf. Gjb bs gurfr tb qvntbany naq qvqa'g srry ryrtnag fb V gubhtug nobhg gurz svefg, ohg bayl n pbhcyr bs frpbaqf fvapr vg'f vzcbffvoyr gb xabj rknpgyl jvgubhg chggvat qbja gur nofbyhgr yvarf.

    Vg'f fhcre uneq gb cebcreyl rkcynva va jbeqf be rira vzntrf ubj V gubhtug bs vg, V'ir orra cynlvat gur tnzr n yvggyr ovg nyzbfg rirel qnl fb V'ir ohvyg hc vaghvgvba bs ubj pregnva chmmyrf jbexf bhg, naq ubj gur cebcbegvbaf bs gur cynlvat svryq eryngrf gb ubj lbh pbire fbzr svryqf.

    Naljnl urer'f ubj V fbyirq vg:
    uggcf://vzntvmre.vzntrfunpx.hf/i2/386k384d90/633/sr873p.cat

  • #5

    Lalo Martins (Saturday, 19 July 2014 16:23)

    Eh, maybe I'm better than I thought, because I didn't find it particularly difficult. Only twice I got to situations where it could go one of two ways, so I ended up trying potentially 4 combinations. (Not sharing anything wrt technique because I don't think I used anything special… at least nothing not already covered above.)

  • #6

    fserb (Saturday, 19 July 2014 17:33)

    Jung V qvq ba guvf bar jnf: nsgre svyyvat gur boivbhf pbeevqbef, abgvpr gung gur prageny pbeevqbe qvivqrf gur obneq va gjb. Guvf zrnaf gung gur bcra 4 cvrprf va gur zvqqyr bs gur obneq unir gb or ubevmbagny (orpnhfr vs gurl jrer iregvpny, gur obneq jbhyq or fcyvg va gjb).
    Guvf zrnaf gung rnpu fvqr bs gur obneq (nf qvivqrq ol guvf prageny pbyhza) unf 2 pbaarpgvbaf gb gur bgure fvqr, juvpu zrnaf gung obgu rkvgf zhfg or ba gur fnzr fvqr (V pnyy guvf "orpnhfr bs Xbavtforet", juvpu vf gur Rhyre ernfbavat gb fbyir gur Xbavtforet oevqtrf ceboyrz).
    Ohg abgvpr gung, ng gur zbzrag lbh qb guvf, lbh ner sbeprq ba gur obggbz yrsg fvqr gb znxr na rkvg gurer. Juvpu zrnaf gung (orpnhfr bs Xbavtforet) gur gbc yrsg fvqr vf nyfb na rkvg.
    Sebz gurer, vg'f cerggl rnfl gb fbyir gur jubyr evtug fvqr naq gb svavfu gur yrsg fvqr.

  • #7

    Jérôme Morin-Drouin (Saturday, 19 July 2014 20:00)

    That's very interesting! An additional challenge is to prove that the solution is unique. This leaves chance outside of the equation, but not intuition. Anyway, here is how I started it:

    Gur ebbz ba gur evtug (T1:W10) unf 4 rkvgf. Hfvat nyy sbhe qba'g jbex, fb jr arrq gb hfr bayl 2, naq nyy cnvef dhvpxyl yrnq gb n pbagenqvpgvba rkprcg T1 naq T10. Guhf, gur 2 rkvgf ba gur evtug zhfg or pybfrq, naq gur 2 rkvgf ba gur yrsg zhfg or hfrq. Gur erfg sybjf fzbbguyl.

  • #8

    Rigulel (Saturday, 19 July 2014 21:09)

    how I solved it:
    1.svyy va gur fdhnerf jvgu gjb jnyyf nebhaq gurz
    2.cebir gung gur obggbz evtug rkvg vfa'g hfrq: tbvat evtug va t10 vf vzcbffvoyr orpnhfr gura ebbz t1-w9 arrqf gjb rkvgf naq bayl unf bar. tbvat hc vf t10 vf nyfb vzcbffvoyr (V pna'g cebir guvf hfvat jbeqf ohg gurer vf ab jnl sbe gur yvar gb cnff rirel fdhner va fnvq ebbz).
    3.cebir gung gbc evtug rkvg vfa'g hfrq va rknpgyl gur fnzr jnl
    4.svyy va ebbz t1-w10, juvpu abj unf gjb rkvgf
    5.ebbz n1-q10 abj unf 4 rkvgf nyy bs juvpu zhfg or hfrq, cerggl rnfl gb fbyir gur chmmyr sebz urer

  • #9

    Allan (Saturday, 19 July 2014 22:46)

    I created an Imgur album describing how I got to the solution: http://imgur.com/a/fPtWE

    Although when I first did the puzzle I worked on both sides simultaneously, here I did one side at a time for clarity.

  • #10

    Edderiofer (Sunday, 20 July 2014 09:00)

    Well done, everyone; it looks like many of you got the intended breakin. I should make a harder one.

    To be entirely honest, on a scale of 1 to 10, where 1 is "trivial", and 10 is "so difficult that even brute force has problems solving it", I would give this one perhaps a 7, and the hardest puzzle in the app perhaps a 5. Most of the puzzles in the app are at difficulties 3 to 4.

    Also, I would very much like to see someone construct a harder puzzle than this. If you can, then send it over to Jerome's email!

    --Edd.

  • #11

    Adrian Wood (Sunday, 20 July 2014 11:01)

    Hint for people having trouble starting:

    Lbh pna guvax bs guvf nf orvat gjb gnyy, 4-pryy-jvqr ebbzf ba rnpu fvqr jvgu n qvivqre va gur zvqqyr. Fgneg ol guvaxvat nobhg ubj gubfr gjb nernf pbhyq yvax, naq gur erfg jvyy sbyybj.

  • #12

    John Kaniarz (Sunday, 20 July 2014 17:57)

    @Edderiofer I think that if you didn't give: gur serrovrf ba gur gbc naq obggbz bs gur evtug unaq fvqr. Then reworked it a little bit to make the solution unique again it would be much harder. (Assuming that it can be reworked without making it trivial.)

    Also, here's a solving trick that nobody mentioned but Jerome alluded to with "It quickly leads to a contradiction".
    Gur chmmyr unf na rira ahzore bs fdhnerf, fb lbh xabj gung bar rkvg vf juvgr naq bar rkvg vf oynpx. Gur fnzr nccyvrf sbe gur evtug fhofrpgvba (T1:W10) bs gur chmmyr. Ivn dhvpx vafcrpgvba, n cngu sebz T1 gb W10 be T10 gb W1 ner whfg abg cbffvoyr orpnhfr gurl ner gur fnzr pbybe.

    Vs lbh nffhzr gung W1 vf gur rkvg gura lbh'er sbeprq gb znxr n yvar sebz S1 gb W1 gura bhg qhr gb gur serrovrf ng U1,V1. Gur ybtvp nccyvrf gb rkvg ng W10.

  • #13

    Tetragon (Tuesday, 22 July 2014 09:08)

    V sbhaq n srj guvatf lbh pna qb jvgu gur erpgnatyrf va gur evtug fvqr, gur 4 ol 2 barf... lbh jbhyq guvax gung ol ybbxvat ng vg, gurer ner 7 cbffvoyr nccrnenaprf vg pna gnxr, ohg guerr bs gurz eraqre gurer orvat bar fbyhgvba vainyvq, guhf erzbivat guerr bs gurz naq erqhpvat vg gb sbhe, rkprcg sbe gur zvqqyr bar juvpu bayl unf guerr... Ol qbvat gur onfvpf, lbh unir cynprq yvarf sbe nyy gur aneebj cnffntrf, fb jvgu gjb bs gurfr erpgnatyrf, lbh'yy frr gung yvarf pna'g or vasvavgr ybbcf, fb gung ryvzvangrf n cbffvovyvgl sbe gjb bs gurfr erpgnatyrf naq gur erznvavat cbfvgvbaf sbe yvarf, funer fcrpxf va pbzzba, juvpu pna or znexrq... nf sbe gur zvqqyr erpgnatyr, vg nyernql unf guerr cbffvovyvgvrf, gurer jbhyq or guerr zber cbffvoyr nccrnenaprf, ohg gung jbhyq vainyvqngr havdhr fbyhgvbaf...

  • #14

    Tetragon (Tuesday, 22 July 2014 09:23)

    For more minor hints:
    1.
    Guvax nobhg ybbcf

    2.
    Rnpu fbyhgvba vf havdhr

    3.
    V sbhaq gur fbyhgvba fgnegvat sebz gur evtug

  • #15

    Tetragon (Tuesday, 22 July 2014 09:40)

    Oh, I found a simple elegant solution:

    Qb nyy gur onfvpf naq ernq bar bs zl ynfg pbzzragf nobhg gur guerr erpgnatyrf ba gur evtug fvqr bs gur fperra... Bar guvat lbh arrq gb xrrc va zvaq, nobhg gur frpgvba ertneqvat gur guerr erpgnatyrf naq gur jnyyf ba gur zvqqyr evtug rqtr, vf gung lbh pna'g unir yvarf ragrevat obgu 3T naq 3W sebz gur abegu, be vs lbh ybbx nurnq, lbh'yy perngr n qrnq raq be na vasvavgr ybbc jvguva gung frpgvba, ertneqvat guvf nern, guvf bayl zrnaf bar yvar tbrf guebhtu guvf ragver nern, abg gjb, fb yvxr n fznyyre chmmyr, gurer vf bar jnl va naq bar jnl bhg... sbphf ba gur gbc evtug rkvg, jvgu na rkcrevzrag, lbh pna cebir gung gur yvar qbrfa'g tb bhg guvf rkvg, fb gel naq pbaarpg vg gb 10W gura pbaarpg 10T qbja fbhgu naq gel gb fbyir vg sebz gurer, lbh'yy eha vagb n qrnq raq fb guvf vf snyfr, guvf zrnaf, 10W yrnqf fbhgu naq 10T yrnqf jrfg, hfvat fvzcyr ybtvp, lbh fubhyq or noyr gb fbyir gur ragver evtug fvqr bs gur fperra, nalguvat orlbaq Q fubhyq or fbyirq... nyfb fvapr lbh ryvzvangrq gjb bs gur rkvgf, gur ynfg gjb rkvgf zhfg or gur bayl jnlf va naq bhg ... Arkg, guvax nobhg 7O, fubhyq vg yrnq yrsg be yrnq evtug... vs lbh gel yrnqvat vg gb gur jrfg, lbh'yy svaq gung vg qbrfa'g jbex, fb yrnq vg gb gur rnfg, gura gur erfg vf rnfl...

  • #16

    Michael (Thursday, 21 January 2016 23:05)

    Vgf nyy nobhg qviretvat cnguf naq pbagenqvpgvbaf jvguva gur qrfvta bs gur chmmyr. Nybat jvgu
    I found an elegent step, which in turn led to an elegent solution:

    nygreangvir naq vagrepbaarpgvat cngujnlf.

    OVT UVAG:

    Ba ba bayl bar fvqr(obgu gbc naq obggbz) qb gur tncf va gur chmmyr arrq gb or pbaarpgrq vqrcraqragyl.

  • #17

    Ger (Tuesday, 16 February 2016 15:41)

    Like Lalo, i don't see what is exactly hard about this puzzle. I solved it in, like, two, three minutes and i really can't say how. Why is this puzzle a 7 on a scale of 1-10? In the app ('at most 5's) i'm about halfway and not progressing much. Admitted, i'm not using any fancy strategies other than de corner and pipes one. Just intuition, trail and error.

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