Transporter by Gomatamago
or solve online (using our beta test of Penpa-Edit tools in linex mode where left click+drag draws lines and right click marks X’s)
Theme: Clue Symmetry and Logic
Author/Opus: This is the 2nd puzzle from guest contributor Gomatamago.
Rules: Draw a route that starts at the gray Start circle (S) and passes through adjacent cells without crossing itself or revisiting any cells. Some cells may not be part of the route. White circles with letters represent packages that are to be picked up and delivered to the black circles marked with the same letter. The carrier has a maximum capacity of packages that can be handled at once, shown below the grid. The carrier must pick up and deliver all packages on the route, returning to S with no packages in hand.
Also see this example:
Answer String: Enter the number of turns in each row, starting at the top and proceeding to the bottom. This example has the answer “224244”.
Time Standards (highlight to view): Grandmaster = 3:00, Master = 12:00, Expert = 24:00
Solution: PDF; a solution video is also available here.
Note: Follow this link for other Loop/Path puzzles.
This one felt a lot more like a numberlink, in that I mostly eyeballed the solving path and wouldn’t be able to prove uniqueness. Is that typical for this puzzle type or am I just missing a few tricks?
Just as JuffoWup said, I wasn’t able to prove uniqueness with this one. I had to stare at the puzzle for a good 10-15 minutes with no clue whatsoever what to do, although (rot13) V unq n uhapu nobhg gur pbearef bs gur chmmyr gung ghearq bhg gb or pbzcyrgryl pbeerpg. Interestingly, even though I did prove uniqueness on the easier Transporter, with both of these the first 10% was excruciatingly difficult, but the last 90% almost seemed to solve itself. Very fun puzzle type, though.
Also, these Transporter puzzles HEAVILY remind me of a game called Cosmic Express. I wonder if there was any inspiration that influenced one or the other?
There are some logical deductions that allow avoidance of guessing on this harder puzzle. However, since the puzzle type is new to this site (and I would welcome more of it and also noticed that Cosmic Express encoded a similar puzzle type except start != end in that game), I shall refrain from putting it here now. Except: Abgvpr gung gur pnc vf 3. Abgvpr gur pneevre znl arire ubyq n naq p ng gur fnzr gvzr. Abgvpr juvpu cnguf ner guhf oybpxrq.
Our solving video (for subscribers) tried to cover the “logical” path here although we understand how some will consider it intuitive. Besides Loren’s tip, which is very useful, you also need to: svaq gur ynfg fgbc orsber lbh erghea gb gur fgneg (v.r., jbex onpxjneqf) — gurer vf bayl bar yrggre vg pna or, naq bapr lbh znex gubfr frtzragf naq gur n naq p pnaabg gbhpu frtzragf, lbh’ir qvivqrq fb zhpu bs gur tevq gung trggvat obgu o cnpxntrf naq qryvirevat gurz vf dhvgr yvzvgvat.
I said I would hate to prove uniqueness but I finally knuckled under and did so. Thomas made a good choice here! My takeaway on solving this type is that nyy bs gur fnzr yrggre pna or ertneqrq nf n tybo gung pnaabg or phg guebhtu ohg pna or nqqrq gb ol bgure yrggre-tebhcf. Vs gur bayl jnl gb perngr cnguf vagb naq bhg bs rnpu tybo vf gb fjnyybj nabgure yrggre-tebhc, gur cvpxhcf ner cebinoyl zvkrq. Pnershy va-bhg cngu pbhagvat naq qverpgvbany phrf cebivqr gur arprffnel sbeprf. Still likely to solve intuitively though.