Detect rotated strings

Question

Read two strings from stdin.
Output Yes if one string is a rotated version of the other.
Otherwise output No

Testcases

Input

CodeGolf GolfCode

Output

Yes

Input

stackexchange changestackex

Output

Yes

Input

stackexchange changestack

Output

No

Input

Hello World

Output

No

Should it really be a rotation or is a combination fine too? eg. what will Stackexchange Stackchangeex return? — jpjacobs, Mar 9, 2011 at 12:08
@Eelvex, yes. @jpjacobs, It would return No. The rotation is a shift, like those LED scrolling signs — gnibbler, Mar 9, 2011 at 12:19
Are the strings always whitespace-free and separated by whitespace? — Joey, Mar 9, 2011 at 15:20
More specifically, what characters are allowed in those strings? — Joey, Mar 9, 2011 at 15:48

steenslag · Accepted Answer · 2011-03-15 08:55:33Z

19

Ruby 49 41

a,b=$*;puts (a*2).sub(b,'')==a ?:yes: :no

Edit: replaced gets.split by $*

edited Mar 15, 2011 at 8:55

answered Mar 9, 2011 at 21:31

steenslag

2,15014 silver badges21 bronze badges

\$\begingroup\$ That's an ingenious idea. \$\endgroup\$
– Joey
Mar 9, 2011 at 21:40
\$\begingroup\$ Very clever. :) \$\endgroup\$
– st0le
Mar 18, 2011 at 4:56
\$\begingroup\$ $* is argv when the question specified stdin though. \$\endgroup\$
– Mathieu CAROFF
Nov 19, 2018 at 1:00

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marinus · Accepted Answer · 2012-05-29 11:53:38Z

APL (28)

Takes input on two lines.

'No' 'Yes'[1+(⊂⍞)∊⌽∘A¨⍳⍴A←⍞]

Explanation:

A←⍞: read a line of input and store it in A
⌽∘A¨⍳⍴A: Rotate A by x, for each x in [1..length A]. Gives a list, i.e. estT stTe tTes Test
(⊂⍞)∊: read another line of input, and see if it is in this list.
1+: add one to this, giving 1 if the strings were not rotated and 2 if they were
'No' 'Yes'[...]: Select either the first or second element from the list 'No' 'Yes' depending on whether the strings were rotated or not.
This value is output automatically.

caird coinheringaahin g · Accepted Answer · 2017-12-15 19:41:20Z

7

Python, 70 bytes

a,b=raw_input().split()
print ['No','Yes'][a in b*2and len(a)==len(b)]

Testing ...

edited Dec 15, 2017 at 19:41

caird coinheringaahin g♦

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answered Mar 9, 2011 at 14:45

Quixotic

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\$\begingroup\$ +1 Nice, selecting the result from an array is clever! :-) \$\endgroup\$
– Tamara Wijsman
Mar 9, 2011 at 15:24
3

\$\begingroup\$ The question states you should read two strings from stdin, which this solution does not. \$\endgroup\$
– Ventero
Mar 9, 2011 at 15:36
\$\begingroup\$ @Ventero:Fixed. \$\endgroup\$
– Quixotic
Mar 9, 2011 at 18:43
1

\$\begingroup\$ You can skip the space in print ['No \$\endgroup\$
– movatica
Aug 12, 2019 at 18:54

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fR0DDY · Accepted Answer · 2011-03-13 14:26:15Z

6

Python 70 Characters

a,b=raw_input().split()
print'YNeos'[len(a)<>len(b)or a not in 2*b::2]

Thanks to gnibbler for the slice trick.

edited Mar 13, 2011 at 14:26

answered Mar 9, 2011 at 14:11

fR0DDY

4,56925 silver badges36 bronze badges

1

\$\begingroup\$ Same problem as the GolfScript solution: If you input nn nfn, you get Yes, which is wrong. \$\endgroup\$
– Tamara Wijsman
Mar 9, 2011 at 14:28
\$\begingroup\$ @TomWij Thanks for finding the bug. Corrected. Should work now. \$\endgroup\$
– fR0DDY
Mar 9, 2011 at 15:14
\$\begingroup\$ You can replace <> by - as that will also result in 0 if they are of equal length. \$\endgroup\$
– Tamara Wijsman
Mar 9, 2011 at 15:28
\$\begingroup\$ But what if they are not of equal length? Then it doesn't work so well :-) \$\endgroup\$
– hallvabo
Mar 13, 2011 at 13:38
\$\begingroup\$ @hallvabo then the strings are not rotated version of each other. \$\endgroup\$
– fR0DDY
Mar 13, 2011 at 13:52

| Show 3 more comments

Eelvex · Accepted Answer · 2011-03-09 13:27:19Z

5

J, 47

y=:>2{ARGV
(>1{ARGV e.1|.^:(i.#y)y){'No',:'Yes'

edited Mar 9, 2011 at 13:27

answered Mar 9, 2011 at 13:11

Eelvex

5,4521 gold badge27 silver badges43 bronze badges

\$\begingroup\$ Why the two J answers? \$\endgroup\$
– J B
Mar 9, 2011 at 19:49
\$\begingroup\$ @JB: because this one uses the buildin rotate. Both answers su^H^H are not so good btw. There is a lot of room for golfing. \$\endgroup\$
– Eelvex
Mar 9, 2011 at 19:57
\$\begingroup\$ why the other one, then, I'm tempted to ask? :-) \$\endgroup\$
– J B
Mar 9, 2011 at 20:06
\$\begingroup\$ @JB: because I thought this one is barely legal ( :p ) [ while the other one extends nicely to lisp. ] \$\endgroup\$
– Eelvex
Mar 9, 2011 at 20:13
\$\begingroup\$ errr... the other one seems to read input from the command-line as well \$\endgroup\$
– J B
Mar 9, 2011 at 20:15

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rubber boots · Accepted Answer · 2011-03-09 15:33:52Z

5

According to the spec (same string lengths):

Perl, 42 43 chars

$.=pop;$_=(pop)x2;print+(qw'yes no')[!/$./]

If different sized strings are allowed, the solution would be:

Perl, 47 chars

$.=(pop)x8;$_=(pop)x9;print+(qw'yes no')[!/$./]

rbo

edited Mar 9, 2011 at 15:33

answered Mar 9, 2011 at 14:11

rubber boots

1,0147 silver badges6 bronze badges

\$\begingroup\$ Same problem as the GolfScript solution: If you input nn nfn, you get Yes, which is wrong. \$\endgroup\$
– Tamara Wijsman
Mar 9, 2011 at 14:17
1

\$\begingroup\$ seems to be ok (I missed the'!' in the first version) "nn nfn" => no "CodeGolf GolfCode" => yes \$\endgroup\$
– rubber boots
Mar 9, 2011 at 14:22

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Community · Accepted Answer · 2020-06-17 09:04:33Z

5

Golfscript, 31

' '/:)~,\,=)~.+\/,(&'Yes''No'if

This one check length first, so it should work as expected.

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Mar 19, 2011 at 6:23

YOU

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\$\begingroup\$ :) and =) +1 for very happy code \$\endgroup\$
– TuxCrafting
Oct 30, 2016 at 23:48

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J B · Accepted Answer · 2011-03-09 20:35:33Z

4

J, 57

{&('No';'Yes')@-:/@:((/:~@(|."0 _~i.&$))&.>)&.(;:&stdin)_

Sample use:

$ echo -n CodeGolf GolfCode | jconsole rotate.ijs
Yes
$ echo -n stackexchange changestackex | jconsole rotate.ijs
Yes
$ echo -n stackexchange changestack | jconsole rotate.ijs
No
$ echo -n Hello World | jconsole rotate.ijs
No

answered Mar 9, 2011 at 20:35

J B

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Community · Accepted Answer · 2020-06-17 09:04:33Z

3

Windows PowerShell, 76

$a,$b=-split$input
('No','Yes')[+!($a.length-$b.length)*"$b$b".contains($a)]

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Mar 9, 2011 at 17:11

Joey

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ecatmur · Accepted Answer · 2011-03-13 22:11:51Z

3

JavaScript, 51

function f(a,b)a&&(a+a).replace(b,"")==a?"Yes":"No"

JavaScript doesn't have a canonical host, so this answer is written as a function of two arguments. The score goes up to 60 if we disallow JS 1.7 features (expression closures).

In the SpiderMonkey shell this would be (for a score of 71):

[a,b]=readline().split(" ");print(a&&(a+a).replace(b,"")==a?"Yes":"No")

answered Mar 13, 2011 at 22:11

ecatmur

1,68510 silver badges15 bronze badges

\$\begingroup\$ 5 years later and now you can use the => function notation ;) \$\endgroup\$
– J Atkin
Feb 23, 2016 at 1:28

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Coding man · Accepted Answer · 2014-03-12 05:12:20Z

3

Python, 66 63

a,b=raw_input().split()
print'YNeos'[a!=(2*a).replace(b,"")::2]

Another solution in 69 char

a,b=raw_input().split()
print['No','Yes'][a in b*2and len(a)==len(b)]

edited Mar 12, 2014 at 5:12

answered Oct 18, 2013 at 13:19

Coding man

1,3259 silver badges19 bronze badges

2

\$\begingroup\$ print'YNeos'[a!=(2*a).replace(b,"")::2] \$\endgroup\$
– gnibbler
Oct 19, 2013 at 10:05
\$\begingroup\$ @gnibbler nice trick, thanks for suggestion. I updated the code \$\endgroup\$
– Coding man
Oct 19, 2013 at 11:26

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Eelvex · Accepted Answer · 2011-03-09 12:52:06Z

2

J, 84

y=:(>1{ARGV),:(>2{ARGV)
((0{y)e.(y&((]$0{[),(]-~[:}.[:$[)$1{[)/.i.}.$y)){'No',:'Yes'

answered Mar 9, 2011 at 12:52

Eelvex

5,4521 gold badge27 silver badges43 bronze badges

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Sergio Cinos · Accepted Answer · 2011-03-09 14:44:34Z

2

JavaScript (120 chars)

function f(a,b) {for (i=0,A=a.split("");A.join("")!=b&&i++<a.length;A.push(A.shift()));return A.join("")==b?'Yes':'No';}

Output:

f('CodeGolf','GolfCode'); //Yes
f('stackexchange','changestackex'); //Yes
f('stackexchange','changestack'); //No
f('Hello','World'); //No
f('nn','nBn'); //No

answered Mar 9, 2011 at 14:44

Sergio Cinos

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Ventero · Accepted Answer · 2011-03-09 15:47:09Z

2

Ruby, 58 (62) characters

a,b=gets.split;$><<(a.size==b.size&&/#{a}/=~b*2?:Yes: :No)

This solution assumes the input contains only alphanumeric characters (actually everything that doesn't have a special meaning inside a regular expression is ok).

A solution that doesn't have this constraint is 4 characters longer

a,b=gets.split;$><<(a.size==b.size&&(b*2).index(a)?:Yes: :No)

edited Mar 9, 2011 at 15:47

answered Mar 9, 2011 at 15:34

Ventero

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Tamara Wijsman · Accepted Answer · 2011-03-09 18:44:30Z

2

Python, 71

a,b=raw_input().split()
print'Yes'if a in b*2and len(a)==len(b)else'No'

edited Mar 9, 2011 at 18:44

answered Mar 9, 2011 at 13:22

Tamara Wijsman

1214 bronze badges

\$\begingroup\$ Same problem as the GolfScript solution: If you input nn nfn, you get Yes, which is wrong. \$\endgroup\$
– Timwi
Mar 9, 2011 at 14:08
\$\begingroup\$ Problem has been solved, remains low... :-) \$\endgroup\$
– Tamara Wijsman
Mar 9, 2011 at 14:17
\$\begingroup\$ Doesn't read from stdin as specified. \$\endgroup\$
– Wooble
Mar 9, 2011 at 16:57
\$\begingroup\$ Now it does... :-) \$\endgroup\$
– Tamara Wijsman
Mar 9, 2011 at 18:59

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Daniel · Accepted Answer · 2011-03-20 16:45:28Z

2

PHP, 61

<?echo preg_match('/^(.+)(.*) \\2\\1$/',fgets(STDIN))?Yes:No;

edited Mar 20, 2011 at 16:45

answered Mar 20, 2011 at 16:30

Daniel

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Daniel · Accepted Answer · 2011-04-11 20:16:27Z

2

Ruby, 41

puts gets =~ /^(.+)(.*) \2\1$/ ?:Yes: :No

edited Apr 11, 2011 at 20:16

answered Mar 20, 2011 at 16:40

Daniel

1513 bronze badges

\$\begingroup\$ Doesn't print anything, results in ':No' for input 'aaa aaa' (on my machine). The regexp approach could be a good idea though. \$\endgroup\$
– steenslag
Mar 25, 2011 at 0:43
\$\begingroup\$ Fix to actually print and input from stdin instead of args: puts gets =~ /^(.+)(.*) \2\1$/ ?:Yes: :No - ups it to 41 chars. \$\endgroup\$
– Nemo157
Mar 25, 2011 at 4:12

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score 2 · Accepted Answer · 2011-04-15 03:41:45Z

2

Haskell (98 96 chars)

g x y@(t:r)(z:w)|x==y="Yes"|1>0=g x(r++[t])w
g _ _[]="No"
f(x:y:_)=g x y y
main=interact$f.words

edited Apr 15, 2011 at 3:41

answered Mar 15, 2011 at 8:16

user1011

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skeevey · Accepted Answer · 2012-05-30 15:39:39Z

2

Q (50 43 chars)

{`No`Yes x in((!)(#)y)rotate\:y}." "vs(0:)0

edited May 30, 2012 at 15:39

answered May 29, 2012 at 21:32

skeevey

4,36518 silver badges22 bronze badges

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Don Mackenzie · Accepted Answer · 2012-05-31 15:53:47Z

2

Scala 78

val b=readLine split " "
print(b(0).size==b(1).size&&(b(0)+b(0)contains b(1)))

It's a shame about the size check, without it the count drops to 54

val a=readLine split " "
print(a(0)+a(0)contains a(1))

answered May 31, 2012 at 15:53

Don Mackenzie

1312 bronze badges

\$\begingroup\$ """val b=readLine split " " print(b(0).sorted==b(1).sorted)""".length yields 56 \$\endgroup\$
– user unknown
Jun 1, 2012 at 3:49

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Community · Accepted Answer · 2020-06-17 09:04:33Z

2

bash 56

read a b
[[ $a$a =~ $b&&$b$b =~ $a ]]&&echo Yes||echo No

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered May 30, 2012 at 6:22

user unknown

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Dennis · Accepted Answer · 2014-05-10 02:46:38Z

GolfScript, 25 bytes

' '/~.2*@/''+='Yes''No'if

How it works

             # STACK: "CodeGolf GolfCode"
' '/         # Split input string by spaces.
             # STACK: [ "CodeGolf" "GolfCode" ]
~            # Dump the array.
             # STACK: "CodeGolf" "GolfCode"
.            # Duplicate the topmost string.
             # STACK: "CodeGolf" "GolfCode" "GolfCode"
2*           # Repeat the topmost string.
             # STACK: "CodeGolf" "GolfCode" "GolfCodeGolfCode"
@            # Rotate the three topmost strings.
             # STACK: "GolfCode" "GolfCodeGolfCode" "CodeGolf"
/            # Split the second topmost string around the topmost one.
             # STACK: "GolfCode" [ "Golf" "Code" ]
''+          # Flatten the array of strings.
             # STACK: "GolfCode" "GolfCode"
=            # Check for equality.
             # STACK: 1
'Yes''No'if  # Push 'Yes' for 1, 'No' for 0.
             # STACK: "Yes"

A Simmons · Accepted Answer · 2016-05-10 16:06:57Z

2

CJam, 21 bytes

r]r_,,\f{\{(+}*}_@+^!

Try it online!

answered May 10, 2016 at 16:06

A Simmons

4,6051 gold badge12 silver badges21 bronze badges

\$\begingroup\$ This answer seems to return 0/1 instead of No/Yes. \$\endgroup\$
– ბიმო
Dec 15, 2017 at 20:12

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ბიმო · Accepted Answer · 2017-12-15 20:19:30Z

Husk, 14 bytes

Not sure about the rules here, Husk doesn't do IO at all. The closest alternative is a function:

!w¨Ye∫No¨€U¡ṙ1

Try it online!

Explanation

!w¨Ye∫No¨€U¡ṙ1
           ¡    -- iterate the following for ever:
            ṙ1  --   rotate string by 1
          U     -- only keep the longest prefix with unique elements
         €      -- is the argument in that list?
  ¨Ye∫No¨       -- compressed string: "Yes No"
 w              -- split on space
!               -- modular index (1-based)

caird coinheringaahin g · Accepted Answer · 2022-02-02 20:34:04Z

2

Jelly, 17 13 bytes

ɠṙJɠeị“Yes“No

Try it online!

How it works

ɠṙJɠeị“Yes“No - Main link. Takes no arguments
ɠ             - Read a line from STDIN
  J           - Indices; [1, 2, ..., len(S)]
 ṙ            - All rotations of S
   ɠe         - Read a line from STDIN; is that in the rotations?
     ị“Yes“No - Index that into ["Yes", "No"]

edited Feb 2, 2022 at 20:34

answered Dec 15, 2017 at 19:25

caird coinheringaahin g♦

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jpjacobs · Accepted Answer · 2011-03-09 12:16:43Z

1

Lua 115 chars

a,b=io.read():match"(%w+) (%w+)"c=b repeat c=c:sub(2,-1)..c:sub(1,1) s=s or a==c until b==c print(s and"Yes"or"No")

answered Mar 9, 2011 at 12:16

jpjacobs

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Joey Adams · Accepted Answer · 2011-03-09 18:26:15Z

1

C program - 146

char b[99],c[99],*p,*q;main(n){q=(p=b+(n=strlen(gets(c))))+n;sprintf(b,"%s%s"
,c,c);for(gets(c);p>b&&strcmp(p,c);--p,*--q=0);puts(p>b?"Yes":"No");}

answered Mar 9, 2011 at 18:26

Joey Adams

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Kevin Brown-Silva · Accepted Answer · 2011-03-13 22:33:09Z

1

PHP, 82 characters

<?$s=split(" ",fgets(STDIN));echo str_replace($s[1],"",$s[0].$s[0])==$s[0]?Yes:No;

answered Mar 13, 2011 at 22:33

Kevin Brown-Silva

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sogart · Accepted Answer · 2011-03-18 00:27:11Z

1

perl, 123 chars

@s1=split(//,shift);
$s2=shift;
$i=0;
while($i<=@s1){
    if(join("",@s1) eq $s2){die "yes";}
    unshift @s1,pop @s1;
    $i++;
}
die "no";

answered Mar 18, 2011 at 0:27

sogart

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Lowjacker · Accepted Answer · 2011-03-26 15:00:58Z

1

Ruby, 30 37

gets
puts~/^(.+)(.*) \2\1$/?:Yes: :No

A version that prints "true" and "false" instead of "yes" and "no":

gets
p !! ~/^(.+)(.*) \2\1$/

Both of these work with different-length strings (unlike the old one)

edited Mar 26, 2011 at 15:00

answered Mar 24, 2011 at 23:25

Lowjacker

4,8291 gold badge18 silver badges19 bronze badges

\$\begingroup\$ Does work if the two strings have the same length, but fails on input like 'golfcode golf'. \$\endgroup\$
– steenslag
Mar 25, 2011 at 0:37

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Stack Exchange Network

Detect rotated strings

49 Answers 49

Ruby 49 41

APL (28)

Python, 70 bytes

J, 47

Perl, 42 43 chars

Perl, 47 chars

Golfscript, 31

J, 57

Windows PowerShell, 76

JavaScript, 51

Python, 66 63

J, 84

Ruby, 58 (62) characters

Python, 71

PHP, 61

Ruby, 41

Haskell (98 96 chars)

Q (50 43 chars)

bash 56

GolfScript, 25 bytes

How it works

CJam, 21 bytes

Husk, 14 bytes

Explanation

Jelly, 17 13 bytes

How it works

C program - 146

PHP, 82 characters

Ruby, 30 37

Your Answer

Not the answer you're looking for? Browse other questions tagged
code-golf
string
decision-problem
or ask your own question.

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Detect rotated strings

49 Answers 49

Ruby 49 41

APL (28)

Python, 70 bytes

J, 47

Perl, 42 43 chars

Perl, 47 chars

Golfscript, 31

J, 57

Windows PowerShell, 76

JavaScript, 51

Python, 66 63

J, 84

Ruby, 58 (62) characters

Python, 71

PHP, 61

Ruby, 41

Haskell (98 96 chars)

Q (50 43 chars)

bash 56

GolfScript, 25 bytes

How it works

CJam, 21 bytes

Husk, 14 bytes

Explanation

Jelly, 17 13 bytes

How it works

C program - 146

PHP, 82 characters

Ruby, 30 37

Your Answer

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Not the answer you're looking for? Browse other questions tagged
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