3
Given a number determine if it is a circular prime.
A circular prime is a prime where if you rotate the digits you still get prime numbers. 1193 is circular prime because 1931 and 9311 and 3119 are all primes.
Input: Output:
1193 circular
11939 circular
1456 nothing
193939 circular
1111111 nothing
7 circular
23 nothing
Shortest code wins.
Quillion
Posted 2013-11-12T18:00:32.443
Reputation: 809
2
:s,,{)s/(+~:P{(.P\%}do(},!"nothing
circular"n/=
Input must be given on STDIN without trailing newline (online example).
Howard
Posted 2013-11-12T18:00:32.443
Reputation: 23 109
It's beautiful :) – Quillion – 2013-11-15T15:04:31.217
6
('nothing';'circular'){~*/1&p:".(|."0 1~i.&#)":
*/1&p:".(|."0 1~i.&#)":
": is a string conversion; i.&# produces a range of integers [0,len), and |."0 1~ is a rotation of the string by each successive integer of the range.
". converts the list of rotations back into numbers, 1&p: converts the list of numbers into booleans (i.e. "prime?" predicate), and */ is a multiply reduce over the booleans (i.e. and).
rationalis
Posted 2013-11-12T18:00:32.443
Reputation: 456
Wow I really like this :) nicely done – Quillion – 2013-11-13T13:56:12.457
Add an {'nothing';'circular' and beat the Python submission :) – marinus – 2013-11-14T23:46:55.313
1@marinus Done, though it really hurts my sense of aesthetics... The interface between the human and the program is always the least fun to code. – rationalis – 2013-11-15T04:03:51.127
Months after the fact, I finally just realized I could replace [:i.# with i.&#, which was bugging me at the time... L'esprit_de_l'escalier. Take that, GolfScript!
5
p=input();n=`p`
for i in n:
n=n[1:]+n[0];e=2
while`e`!=n:p*=int(n)%e;e+=1
print'cniortchuilnagr'[p<1::2]
Daniel Lubarov
Posted 2013-11-12T18:00:32.443
Reputation: 301
I see what you did there with the answer :) very clever – Quillion – 2013-11-13T15:29:10.537
2Oh man! I just did mine in Python and I came up with "cniortchuilnagr" independently. – danmcardle – 2013-11-14T03:32:30.890
1
Whoa! I got the idea from http://codegolf.stackexchange.com/a/406/9395
– Daniel Lubarov – 2013-11-14T03:38:25.7533You can make this both shorter and correct if you use for i in n... otherwise, this will fail to rule out certain primes with more than 10 digits. – boothby – 2013-11-14T19:02:54.443
@boothby good idea, thanks! – Daniel Lubarov – 2013-11-14T19:47:11.397
5
f@s_ := And @@ PrimeQ[FromDigits@StringRotateLeft[s, #] & /@ Range@9]
Usage
f["1193"]
True
f["11939"]
True
f["1456"]
False
f["193939"]
True
f["1111111"]
False
f["7"]
True
f["23"]
False
DavidC
Posted 2013-11-12T18:00:32.443
Reputation: 24 524
1You can use FromDigits instead of ToExpression. – alephalpha – 2013-11-13T02:27:05.060
I had no idea that FromDigits could handle strings! – DavidC – 2013-11-13T02:34:32.727
3
require'mathn'
x=gets.chop.split''
puts (0..x.size).all?{|n|x.rotate(n).join.to_i.prime?}?:circular:'nothing'
Doorknob
Posted 2013-11-12T18:00:32.443
Reputation: 68 138
1You can shorten 1 character by using Symbol instead of String for :circular. – manatwork – 2013-11-15T09:31:12.657
3
And@@PrimeQ[FromDigits/@NestList[RotateLeft,IntegerDigits@#,9]]&
Marcks Thomas
Posted 2013-11-12T18:00:32.443
Reputation: 141
You can save a few characters by using RotateRight or RotateLeft to rotate the digits. – DavidC – 2013-11-13T00:45:04.863
@DavidCarraher: Thanks, it saves quite a few, actually. How at one point I must have thought my elaborate Part trick would be shorter, I find most puzzling, but even now, you're still a good three characters ahead. – Marcks Thomas – 2013-11-13T13:13:23.827
1
a=scan()
p=0
A=nchar(a)
S=substr
for(i in 1:A){b=as.integer(paste0(S(a,i+1,A),S(a,1,i)));p=p+!sum(!b%%1:b)<3}
c('nothing','circular')[!p+1]
plannapus
Posted 2013-11-12T18:00:32.443
Reputation: 8 610
1
def m():
s=input()
r=range
for i in r(len(s)):
a=int(s)
if all(a%i for i in r(2,a)):return 0
s=s[1:]+s[:1]
return 1
print("cniortchuilnagr"[m()::2])
danmcardle
Posted 2013-11-12T18:00:32.443
Reputation: 695
1
[:x|r:=[:n|(n\\10)*(10 raisedTo:n log floor)+(n//10)].s:=OrderedCollection with:x.[(m:=r value:s last)=x]whileFalse:[s add:m].^(s allSatisfy:[:each|each isPrime])ifTrue:['circular']ifFalse:['nothing']]
formatted
[:x|
r:=[:n|(n\\10)*(10 raisedTo:n log floor)+(n//10)].
s:=OrderedCollection with:x.
[(m:=r value:s last)=x]whileFalse:[s add:m].
^(s allSatisfy:[:each|each isPrime])ifTrue:['circular']ifFalse:['nothing']]
Paul Richter
Posted 2013-11-12T18:00:32.443
Reputation: 770
1
'nothing' 'circular'[1+^/{⌊/⍵|⍨1↓⍳⍵-1}¨⍎¨{⍵⌽∆}¨⍳⍴∆←⍞]
protist
Posted 2013-11-12T18:00:32.443
Reputation: 570
1I don't think this should have the code-challenge tag. – Cruncher – 2013-11-12T19:18:38.223
@Cruncher Wouldn't solving such problem in shortest possible code require creative thinking? If it is not code-challenge then I will gladly remove it, just assumed it to be challenge. – Quillion – 2013-11-12T19:34:47.560
1
Not a big deal, but they're sort of disjoint. http://codegolf.stackexchange.com/tags/code-challenge/info "A code challenge is a competition for creative ways to solve a programming puzzle for an objective criterion other than code size."
– Cruncher – 2013-11-12T19:36:59.323@Cruncher sorry about that. Thanks for clarifying it for me :) – Quillion – 2013-11-12T19:42:20.000
4-1 You stated: "Shortest code wins" but awarded the check to a submission that was 4 times as long as the shortest submitted! – DavidC – 2013-11-14T19:50:02.533
@DavidCarraher I asked for specific output. I do not see the shortest answer provide such output. Try running some programs and see if input and output matches for what is requested. – Quillion – 2013-11-14T20:37:31.617
You must be kidding. – DavidC – 2013-11-14T20:56:30.090
@DavidCarraher please do enlighten me which is the answer whose's code if I copy paste and run will yield the output on the given input specified above? – Quillion – 2013-11-14T21:44:34.203
1My own code returns True if a number is circular, False if a number is not circular. I find that a reasonable alternative to "circular" and "nothing". The shorter solution in J appears to follow the same Boolean convention (True, False). – DavidC – 2013-11-14T22:05:55.750
4@DavidCarraher Some problems on this site require specific output. This is one. Deal with it and stop whining. "Oh, poor me, my output
99,98,97...is equivalent to the lyrics of '99 bottles of beer on the wall' but it wasn't an accepted answer!" – boothby – 2013-11-14T22:13:41.6401@Boothby. Bad example. "99 bottles of beer on the wall" is all about crafting a specific output, the lyrics of a song. The present example is advertised a test of circularity of a number: "Given a number determine if it is a circular prime." Example output was given. But it was not stated (nor should it have been, in my view) that that specific format is required). – DavidC – 2013-11-14T22:21:10.260
1@DavidCarraher, It most certainly is stated. despite your wishes to the contrary. Look at the question, and see "Input" and "Output". This is a 'compound question': solve a challenge and format the output. – boothby – 2013-11-15T02:42:56.227