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Timeline for Circular robot instructions

Current License: CC BY-SA 4.0

29 events
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Jun 17, 2020 at 9:04 history edited CommunityBot
Commonmark migration
Feb 26, 2020 at 5:07 vote accept Peter Kagey
S Dec 1, 2019 at 20:22 history bounty ended Peter Kagey
S Dec 1, 2019 at 20:22 history notice removed Peter Kagey
S Nov 30, 2019 at 1:22 history bounty started Peter Kagey
S Nov 30, 2019 at 1:22 history notice added Peter Kagey Reward existing answer
Nov 29, 2019 at 20:22 history edited Peter Kagey CC BY-SA 4.0
Add updated links to Github page.
Nov 29, 2019 at 19:41 comment added Peter Kagey @justhalf, that's right. Its path looks like three circles "ooo", so there are two places where the path self-intersects.
Nov 29, 2019 at 11:28 comment added justhalf In the case 4 [2, 4], is the answer 2? Before making the last full circle it kind of touches the starting point.
Nov 28, 2019 at 22:49 history edited Peter Kagey CC BY-SA 4.0
Update spacing in examples, add another example.
Nov 28, 2019 at 2:21 answer added Alexey Burdin timeline score: 10
Nov 27, 2019 at 22:33 comment added Peter Kagey @flawr, you're right that when \$n \neq 2, 3, 4\$ or \$6\$, paths can come arbitrarily close.
Nov 27, 2019 at 22:29 comment added Peter Kagey @AlexeyBurdin, you're correct that 6 [5,5] has an infinite number of intersections—it was incorrect in the test data, and I've removed it. However, although 6 [1,1] is infinite, it has no intersections, so I think it's valid input. (In particular, if the instructions result in an infinite walk, this means that the walk has no intersections because infinite-intersection instructions are illegal inputs.)
Nov 27, 2019 at 22:27 history edited Peter Kagey CC BY-SA 4.0
deleted 25 characters in body
Nov 27, 2019 at 22:07 comment added Alexey Burdin Shouldn't test cases like 6 [1,1] and 6 [5,5] be excluded as infinite or these are to be handled by the program? Btw, does 6 [5,5] really gives 0 intersections? There will be infinity tangent intersections, IMHO.
Nov 27, 2019 at 21:31 comment added Draco18s no longer trusts SE On the "retraces steps" problem, [1,2,3,4,5,6] does interesting things.
Nov 27, 2019 at 16:29 comment added flawr I think in general counting intersection exactly (i.e. if you don't want people to rely on approximate solutions) is hard - I'm pretty convinced there are paths for some n that let two paths come arbitrarily close.
Nov 27, 2019 at 6:00 history tweeted twitter.com/StackCodeGolf/status/1199568683800104960
Nov 27, 2019 at 2:35 comment added Peter Kagey I've realized that this challenge is equivalent to counting self-intersections in an arbitrary, closed robot walk. If there are tweaks that I can make to the rules to make this challenge more tractable without changing the spirit of the problem, please let me know.
Nov 27, 2019 at 1:53 history edited Peter Kagey CC BY-SA 4.0
Add another constraint on input.
Nov 27, 2019 at 1:37 history edited Peter Kagey CC BY-SA 4.0
added 62 characters in body
Nov 27, 2019 at 1:37 comment added xnor @PeterKagey Nope, I haven't checked whether it's possible.
Nov 27, 2019 at 1:36 comment added Peter Kagey @xnor, do you have an example?
Nov 27, 2019 at 1:36 comment added xnor If the robot goes over the same point 3 or more times, how do we count that for self-intersections?
Nov 27, 2019 at 1:32 comment added Peter Kagey @Arnauld, thanks for the comment. I mentioned this briefly at the end of the "test data" section, but I added it to the "challenge" section now too. Please suggest more clarifying edits if you see anything unclear.
Nov 27, 2019 at 1:31 history edited Peter Kagey CC BY-SA 4.0
added 78 characters in body; edited tags
Nov 27, 2019 at 1:31 history edited Jo King
edited tags
Nov 27, 2019 at 1:25 history edited Peter Kagey CC BY-SA 4.0
added 137 characters in body
Nov 27, 2019 at 1:18 history asked Peter Kagey CC BY-SA 4.0