Determine si todos los dígitos decimales son únicos

37

Las preguntas eliminadas en Stack Overflow a veces son un excelente material de golf.

Escriba una función que tome un entero no negativo como entrada y devuelva verdadero si todos los dígitos en la representación de base 10 de ese número son únicos. Ejemplo:

48778584 -> false
17308459 -> true

El recuento de caracteres incluye solo la función.

Si elige responder en C o C ++: sin macros, sin comportamiento indefinido; El comportamiento definido por la implementación y las advertencias del compilador están bien.

Thomas
fuente
Todavía estaría interesado en otras soluciones C o C ++ según la pregunta que inspiró esta.
Thomas
1
¿Por qué no hay macros C o C ++ o comportamiento indefinido? Eso es extrañamente limitante a solo dos idiomas.
dfeuer

Respuestas:

31

Golfscript, 8 7 caracteres:

{`..&=}
  • ` - stringify el argumento
  • .. - clonar dos veces
  • & - intersectarse consigo mismo (eliminar duplicados)
  • = - Verificar la igualdad.

si la función necesita ser nombrada (109 caracteres ):

{`..&=}:a

si un programa es suficiente (5 54 caracteres ):

..&=
John Dvorak
fuente
55
La parte difícil de desafíos como este es ser el primero en verlo.
primo
1
@primo todavía, de alguna manera, todavía obtienen un puntaje de +6 en medio día.
John Dvorak
1
@JanDvorak Ley de trivialidad en el trabajo de Parkinson
Claudiu
2
@ Claudiu Puedes entender la ley. Date cuenta de que estás siendo sometido a eso. Luego vota la respuesta de todos modos.
Cruncher
1
@NathanChere, ¿qué quieres decir? la última (y única) vez que se sugirió esa laguna se redujo a -3 antes de que el sugerente la eliminara a la mañana siguiente. Si no le gustan las respuestas de golfscript, no las vote.
John Dvorak el
24

Pitón 2 (28) (32)

lambda n:10**len(set(`n`))>n

Los backticks toman la representación de cadena. La conversión a un conjunto elimina duplicados, y verificamos si esto disminuye la longitud en comparación con 10 ^ d, que es más grande que todos los números de dígitos d pero sin números de dígitos (d + 1).

Código antiguo

lambda n:len(set(`n`))==len(`n`)

xnor
fuente
1
Ha I had this exact same answer ready, just replace n with i
Claudiu
1
@Claudiu so did I. f=lambda _:len(`_`)==len(set(`_`))
Oberon
Yeah, with these bite-size challenges, everyone is going to converge on pretty much the same thing. I was also trying lambda n:max(map('n'.count,'n'))<2 (the single quotes are backticks), but it's two chars longer.
xnor
16

APL (6)

≡∘∪⍨∘⍕

One of the few times where tacit style is shorter in APL too.

It's 8 characters to give it a name,

f←≡∘∪⍨∘⍕

but that's not necessary to use it:

      ≡∘∪⍨∘⍕ 199
0
      ≡∘∪⍨∘⍕ 198
1
      f←≡∘∪⍨∘⍕
      f¨ 198 199 200 201
1 0 0 1
      ≡∘∪⍨∘⍕¨ 198 199 200 201
1 0 0 1
marinus
fuente
1
I think the second jot can be removed to make it 5. It would still be a valid function by itself (though it would require grouping parens to use it with each operator in the last example).
user46915
11

Perl, 19 characters

print<>!~/(\d).*\1/
Tal
fuente
assuming output can be treated as true and no-output can be treated as false, your logic is reversed. You should return true if there's no repetition.
John Dvorak
@JanDvorak Sounds about right. I'll fix that.
Tal
Not-match operator: <>!~/(\d).*\1/.
primo
@primo Thanks! So much to learn :)
Tal
3
The input is specified as being a non-negative integer, so I don't think you need to verify that. If you indeed don't, you can change \d to ..
hvd
9

Rebmμ (10 characters)

e? AtsAuqA

Rebmu's "mushing" trick is that it's case-insensitive, so characters are run together. Whenever a case transition is hit, that splits to the next token. By using transitions instead of a CamelCase kind of thing, the unique choice to start with a capital run means a "set-word" is made. (While set-words can be used for other purposes in symbolic programming, they are evaluated as assignments by default).

So this "unmushes" to:

e? a: ts a uq a

The space is needed because once you've begun a series of runs of alternating cases, you can't use that trick to get a set-word after the first unless you begin a new run. So e?AtsAuqA would have gotten you e? a ts a uq a...no assignment.

(Note: For what may be no particularly good reason, I tend to prefer rethinking solutions so that there are no spaces, if character counts are equal. Since brackets, parentheses, and strings implicitly end a symbol...there are often a fair number of opportunities for this.)

In any case, when mapped to the Rebol that it abbreviates:

equal? a: to-string a unique a

Throwing in some parentheses to help get the gist of the evaluation order:

equal? (a: (to-string a)) (unique a)

So the prefix equality operator is applied to two arguments--the first the result of assigning to a of the string version of itself, and the second the result of unique being run against that string. It so happens that unique will give you back the elements in the same order you passed them...so unique of "31214" is "3124" for instance.

Run it with:

>> rebmu/args "e? AtsAuqA" 17308459             
== true

There's also some stats and debug information:

>> rebmu/args/stats/debug "e? AtsAuqA" 48778584 
Original Rebmu string was: 10 characters.
Rebmu as mushed Rebol block molds to: 10 characters.
Unmushed Rebmu molds to: 15 characters.
Executing: [e? a: ts a uq a]
== false

If the requirement is that one must define a named/reusable function you can make an "A-function" which implicitly takes a parameter named a with a|. (A B-function would be created with b| and take a parameter named A then one named B). So that would add five more characters...let's say you call the function "f"

Fa|[e? AtsAugA]

"You laugh! They laughed at Einstein! Or wait...did they? I...don't know."

Dr. Rebmu
fuente
I used to think the language was pronounced like Reb moo, but now I'm not sure if it's supposed to be Rebum mew or Reb mew or something else.
Justin
2
After playing Nethack, I read Fa|[e? AtsAugA] as False? SomeGibberish
Justin
@Quincunx does s really decay to [ in Nethack?
John Dvorak
@JanDvorak I've seen some letters do decay into [ after some time
Justin
@Quincunx Just playing with the logo. I think REBmu is probably better. Either way, the beard is tight..it pinches. Guess you get what you pay for.
Dr. Rebmu
7

FRACTRAN - 53 38 fractions

47/10 3/5 106/47 3599/54272 53/61 2881/27136 2479/13568 2077/6784 1943/3392 1541/1696 1273/848 1139/424 871/212 737/106 469/53 142/3953 67/71 5/67 1/147 1/363 1/507 1/867 1/1083 1/1587 1/2523 1/2883 1/4107 1/5547 1/7 1/11 1/13 1/17 1/19 1/23 1/29 1/31 1/37 1/43

Uses division to count the number of occurrences of each digit. Call by putting n in register 2 and setting register 5 to 1, gives output in register 3 (0 if false, 1 if true). Also, make sure the rest of your program uses only registers > 71.


Edit 25/12/14: It's been 7 months and we've since gotten Stack Snippets, so here's one to test the code (using my could-be-better interpreter here).

var ITERS_PER_SEC=1E5;var TIMEOUT_MILLISECS=5E3;var ERROR_INPUT="Invalid input";var ERROR_PARSE="Parse error: ";var ERROR_TIMEOUT="Timeout";var ERROR_INTERRUPT="Interrupted by user";var running,instructions,registers,timeout,start_time,iterations;function clear_output(){document.getElementById("output").value="";document.getElementById("stderr").innerHTML=""};function stop(){running=false;document.getElementById("run").disabled=false;document.getElementById("stop").disabled=true;document.getElementById("clear").disabled=false}function interrupt(){error(ERROR_INTERRUPT)}function error(msg){document.getElementById("stderr").innerHTML=msg;stop()}function factorise(n){var factorisation={};var divisor=2;while(n>1){if(n%divisor==0){var power=0;while(n%divisor==0){n/=divisor;power+=1}if(power!=0)factorisation[divisor]=power}divisor+=1}return factorisation};function fact_accumulate(fact1,fact2){for(var reg in fact2)if(reg in fact1)fact1[reg]+=fact2[reg];else fact1[reg]=fact2[reg];return fact1};function exp_to_fact(expression){expression=expression.trim().split(/\s*\*\s*/);var factorisation={};for(var i=0;i<expression.length;++i){var term=expression[i].trim().split(/\s*\^\s*/);if(term.length>2)throw"error";term[0]=parseInt(term[0]);if(isNaN(term[0]))throw"error";if(term.length==2){term[1]=parseInt(term[1]);if(isNaN(term[1]))throw"error";}if(term[0]<=1)continue;var fact_term=factorise(term[0]);if(term.length==2)for(var reg in fact_term)fact_term[reg]*=term[1];factorisation=fact_accumulate(factorisation,fact_term)}return factorisation}function to_instruction(n,d){instruction=[];divisor=2;while(n>1||d>1){if(n%divisor==0||d%divisor==0){reg_offset=0;while(n%divisor==0){reg_offset+=1;n/=divisor}while(d%divisor==0){reg_offset-=1;d/=divisor}if(reg_offset!=0)instruction.push(Array(divisor,reg_offset))}divisor+=1}return instruction};function run(){clear_output();document.getElementById("run").disabled=true;document.getElementById("stop").disabled=false;document.getElementById("clear").disabled=true;timeout=document.getElementById("timeout").checked;var code=document.getElementById("code").value;var input=document.getElementById("input").value;instructions=[];code=code.trim().split(/[\s,]+/);for(i=0;i<code.length;++i){fraction=code[i];split_fraction=fraction.split("/");if(split_fraction.length!=2){error(ERROR_PARSE+fraction);return}numerator=parseInt(split_fraction[0]);denominator=parseInt(split_fraction[1]);if(isNaN(numerator)||isNaN(denominator)){error(ERROR_PARSE+fraction);return}instructions.push(to_instruction(numerator,denominator))}try{registers=exp_to_fact(input)}catch(err){error(ERROR_INPUT);return}running=true;iterations=0;start_time=Date.now();fractran_iter(1)};function regs_to_string(regs){reg_list=Object.keys(regs);reg_list.sort(function(a,b){return a-b});out_str=[];for(var i=0;i<reg_list.length;++i)if(regs[reg_list[i]]!=0)out_str.push(reg_list[i]+"^"+regs[reg_list[i]]);out_str=out_str.join(" * ");if(out_str=="")out_str="1";return out_str};function fractran_iter(niters){if(!running){stop();return}var iter_start_time=Date.now();for(var i=0;i<niters;++i){program_complete=true;for(var instr_ptr=0;instr_ptr<instructions.length;++instr_ptr){instruction=instructions[instr_ptr];perform_instr=true;for(var j=0;j<instruction.length;++j){var reg=instruction[j][0];var offset=instruction[j][1];if(registers[reg]==undefined)registers[reg]=0;if(offset<0&&registers[reg]<-offset){perform_instr=false;break}}if(perform_instr){for(var j=0;j<instruction.length;++j){var reg=instruction[j][0];var offset=instruction[j][1];registers[reg]+=offset}program_complete=false;break}}if(program_complete){document.getElementById("output").value+=regs_to_string(registers);stop();return}iterations++;if(timeout&&Date.now()-start_time>TIMEOUT_MILLISECS){error(ERROR_TIMEOUT);return}}setTimeout(function(){fractran_iter(ITERS_PER_SEC*(Date.now()-iter_start_time)/1E3)},0)};
<div style="font-size:12px;font-family:Verdana, Geneva, sans-serif;"><div style="float:left; width:50%;">Code:<br><textarea id="code" rows="4" style="overflow:scroll;overflow-x:hidden;width:90%;">47/10 3/5 106/47 3599/54272 53/61 2881/27136 2479/13568 2077/6784 1943/3392 1541/1696 1273/848 1139/424 871/212 737/106 469/53 142/3953 67/71 5/67 1/147 1/363 1/507 1/867 1/1083 1/1587 1/2523 1/2883 1/4107 1/5547 1/7 1/11 1/13 1/17 1/19 1/23 1/29 1/31 1/37 1/43</textarea><br>Input:<br><textarea id="input" rows="2" style="overflow:scroll;overflow-x:hidden;width:90%;">2^142857 * 5</textarea><p>Timeout:<input id="timeout" type="checkbox" checked="true"></input></p></div><div style="float:left; width:50%;">Output:<br><textarea id="output" rows="6" style="overflow:scroll;width:90%;"></textarea><p><input id="run" type="button" value="Run" onclick="run()"></input><input id="stop" type="button" value="Stop" onclick="interrupt()" disabled="true"></input><input id="clear" type="button" value="Clear" onclick="clear_output()"></input>&nbsp;<span id="stderr" style="color:red"></span></p></div></div>

Replace 142857 with another number. Output should be 3^1 if true, 1 = 3^0 if false. Takes a while for larger numbers (well, this is FRACTRAN...).

Sp3000
fuente
6

JavaScript - 23 Characters

As a function (ECMAScript 6):

f=x=>!/(.).*\1/.test(x)

Or taking input from a prompt (25 characters)

!/(.).*\1/.test(prompt())
MT0
fuente
6

C# 73 60 59

First golfing for me ...

Write a function that takes a nonnegative integer as input

bool f(int i){return(i+"").Distinct().SequenceEqual(i+"");}

Could strip another character by converting uint to int, but I rather take the task too literally than the other way around. Here we go ...

Num Lock
fuente
1
Some options: i => (i + "").Distinct().SequenceEqual(i + "");
NPSF3000
@NPSF3000 Thanks! Edited my answer. I had something like this on my mind, but oh well ... I totally forgot about +"" calling ToString() under the hood.
Num Lock
A more literal interpretation of "nonnegative integer" suggests that a signed integer will be passed in, but it will never be negative.
Shaz
Well, I guess it will be ok then ...
Num Lock
Use C# 6 and you can use: bool f(int i)=>(i+"").Distinct().SequenceEqual(i+""); (53 bytes)
Stephan Schinkel
5

Ruby (24 bytes)

Use a regular expression to match "some character, followed by zero or more characters, then the same character".

->(s){!!(s !~/(.).*\1/)}

If truthy or falsy values are accepted, rather than literal true or false, then we get 20 characters:

->(s){s !~/(.).*\1/}
John Feminella
fuente
5

C (87)

Since I can't win, I'll go for efficiency.

Function code:

int u(uint32_t d){short s=0,f;while(d){f=1<<d%10;if(s&f)return 0;s|=f;d/=10;}return 1;}
DreamWarrior
fuente
Oh, and since I still can't comment on other people's posts -- I'd like to say that this was a neat solution, even if inaccurate when it "overflows".
DreamWarrior
5

Mathematica, 35 25 characters

(27 if the function needs a name.)

Unequal@@IntegerDigits@#&

EDIT: Saved 8 characters thanks to belisarius!

Martin Ender
fuente
Unequal @@ IntegerDigits@# & could do, I think
Dr. belisarius
@belisarius oh nice, I was looking for something like that but couldn't find it (and didn't think that chained would compare non-adjacent elements). Thanks, that shortens this a lot!
Martin Ender
You don't have to give it a name, right? Unequal@@IntegerDigits@#& is 25 characters.
akater
@Akater true, I can't see a requirement for the name in the challenge. Thanks!
Martin Ender
5

R, 53 51 48 34 Bytes

function(n)!grepl("(.).*\\1",n,,T)

Try it online!

Convert to a string and split. Convert to a table of counts minus 1, sum and negate

Inspired by Most common number answer by Alex and suggestion by Hugh.

A couple saved, thanks to @plannapus One more from @Gregor And a couple from making it an anonymous function

Now with wonderful regex goodness thanks to @J.Doe. This looks for any single char in the number that matches itself else where in the string. The grepl command returns a logical that is then returned. Perl style regexes is set to True.

MickyT
fuente
You can also convert to string using paste0 instead of toString and save 2 characters.
plannapus
You can use paste instead of paste0 to save one more character.
Gregor
@J.Doe: even better ! :)
digEmAll
Used a different approach. 35 bytes with regex.
J.Doe
4

J (9)

Assumes the value to be tested is in variable b (I know this can be made into a function, but don't have a clue on how. J is confusing. Any help on this is appreciated) Thanks Marinus!

(-:~.)@":

Checks if the lenght of the string rep of the number with all the duplicates removed is the same as the lenght of the regular string rep.

ɐɔıʇǝɥʇuʎs
fuente
For a function you can do (-:~.)@":.
marinus
@marinus Oh wow, that's even shorter than I thought. Thanks!
ɐɔıʇǝɥʇuʎs
HI, I found and posted a shorter J solution: -:~.&.":
Galen Ivanov
4

R (70, 60, 53, 52)

Thank you all for the useful comments! Your comments are incorporated in the answer.

### Version 70 chars
f=function(x)!any(duplicated(strsplit(as.character(x),split="")[[1]]))

### Version 60 chars
f=function(x)all(table(strsplit(as.character(x),"")[[1]])<2)

### Version 53 chars
f=function(x)all(table(strsplit(paste(x),"")[[1]])<2)

### Version 52 chars
f=function(x)all(table(strsplit(c(x,""),"")[[1]])<2)

f(48778584)
f(17308459)
djhurio
fuente
@plannapus, you are right. I got confused about "base 10 representation".
djhurio
1
Using table and comparing against 0 instead of duplicated might save some characters
Dason
1
And I think you could leave the split parameter unnamed. I'm just on my phone so can't check easily but I believe it is the second parameter of strsplit so you could use positional instead of named arguments to save characters
Dason
1
And since you already take the first element of the result of strsplit why not coercing x to a character using c(x,"")? f=function(x)all(table(strsplit(c(x,""),"")[[1]])<2) is 1 character shorter :)
plannapus
3

Mathematica (20 19)

(22 21 if function needs a name)

Max@DigitCount@#<2&

or

Max@DigitCount@#|1&

where | ist entered as [Esc]divides[Esc]

branislav
fuente
Nice. I forgot DigitCount existed, and wrote a solution based on conversion to strings. Yours is much better.
Michael Stern
2

C99, 59 chars

a(x){int r=1,f[10]={};for(;x;x/=10)r&=!f[x%10]++;return r;}
Thomas
fuente
C99 doesn't have implicit int, technically.
PatrickB
1
Not just "technically", it was specifically and intentionally removed. This is a syntax error in C99, and aside from a required diagnostic, syntax errors are in the same category as undefined behaviour (explicitly disallowed in the question): if an implementation accepts this, the standard makes no requirements whatsoever about the program's behaviour.
hvd
2

Groovy (36 chars)

f={s="$it" as List;s==s.unique(!1)}

Tested it using:

println f(args[0].toInteger())
Will Lp
fuente
'false' can be golfed via '1==0' or possibly something more clever. Good answer
Michael Easter
@MichaelEaster 0>1 is shorter.
pastebin.com slash 0mr8spkT
1
@ace Yes, though !1 works too...
Michael Easter
@ace, MichaelEaster, thx for the help :-)
Will Lp
@WillP as suggested by MichaelEaster, use !1 instead.
pastebin.com slash 0mr8spkT
2

Haskell:

 import Data.List

 all ((== 1) . length) . group . sort . show
Paul Johnson
fuente
A little late to the party, but since you're importing Data.List anyway I'd suggest nub, which removes duplicates from a List. (\x->nub x==x).show
Flonk
You didnt use pl... main = interact $ show . ap (==) nub . show
kazagistar
2

J (8)

Competely sepertae from my previous answer.

*/@~:@":
ɐɔıʇǝɥʇuʎs
fuente
2

R, 66 65 characters

f=function(x)!sum(duplicated((x%%10^(i<-1:nchar(x)))%/%10^(i-1)))

Separate the digits using integer division and modulo, then check if they are duplicates.

Usage:

> f(48778584)
[1] FALSE
> f(17308459)
[1] TRUE

Or, as @MickyT suggested, for 63 characters:

f=function(x)!anyDuplicated((x%%10^(i<-1:nchar(x)))%/%10^(i-1))
plannapus
fuente
1
You could use anyDuplicated rather than sum and duplicated for 2 more
MickyT
2

C, 58 bytes

f;a(x){for(f=0;x;x/=10)f+=1<<x%10*3;return!(f&920350134);}

Can keep a tally of up to 7 identical digits before rolling over.

in test program (it's easier to see how it works with the constant in octal)

a(x){int f=0;for(;x;x/=10)f+=1<<x%10*3;return!(f&06666666666);}

main(){
scanf("%d",&r);
printf("%o\n",a(r));}

If you happen to have a large power of 2 handy the constant can be calculated like f&(1<<30)/7*6

Level River St
fuente
I think the comment by @xfix was intended for my post instead of yours? You didn't actually used int main(int) in your answer...
pastebin.com slash 0mr8spkT
Having external information that doesn't count towards the code byte/char count is obviously not allowed. I suggest you remove the first version (53 bytes).
2501
Please see my comment in the edit summary.
2501
I voted to reject the edit, but I agree that the counts look wrong. I make them 67 and 63 (61).
Peter Taylor
My edit was rejected by other users. Please re-evaluate it.
2501
1

Javascript 73 chars

function f(n){return !~(n+'').split('').sort().join('').search(/(\d)\1/)}
pllee
fuente
1

Befunge 98, 17 bytes

This is a non-competing answer because Befunge does not have functions.

~:1g1`j@1\[email protected]

Prints a 1 if the number's digits are all unique; otherwise, it just ends.

This works by accessing a cell in the Funge space whose x coordinate is the ASCII value of the character inputted (takes input character by character) and whose y coordinate is 1. If the digit has not been seen before, the value of the cell is 32 (space character). If that is so, I set the value to 1.

As a bonus, this works for non-numbers as well.

Justin
fuente
1

PowerShell - 26

!($args|sls '(.)(?=.*\1)')
Rynant
fuente
1

Perl 6 (19 bytes)

{.comb.uniq==.comb}

.comb splits a string into characters (for example, 42.comb gives "4", "2"). .uniq removes all non-unique characters. .comb characters in string (originally I used .chars, but .comb is shorter). == converts lists into number of elements in it, and compares the numbers. When . is used without object before, $_ which is default function parameter is assumed. {} are function literals.

Konrad Borowski
fuente
1

C, 76

This is no where near winning, but I'll post it anyway just to show an alternative approach.

c;i;a[99];main(){while(~(c=getchar()))a[c]++;for(;i<99;)a[i++]>1&&puts("");}

Prints a new line if false, prints nothing if true.

pastebin.com slash 0mr8spkT
fuente
This program has an undefined behavior. The correct signatures for main are int main(int, char **) or int main(void). int main(int) is not valid.
Konrad Borowski
@xfix I assume main() is ok then?
pastebin.com slash 0mr8spkT
Yes, it's fine. It means the same thing as main(void) (when used in definition, in declaration it declares a function with unknown parameter list).
Konrad Borowski
1

POSIX sh and egrep (47, 43, 40)

f()([ ! `echo $1|egrep '([0-9]).*\1'` ])
  • [-1 char]: Use ! instead of -z with test - Thanks DigitalTrauma
  • [-1 char]: Use `CODE` instead of $(CODE) - Thanks DigitalTrauma
  • [-2 chars]: Use fold -1 instead of grep -o .1 - Thanks DigitalTrauma.
  • [-3 chars]: Check for repeated digits with a backreferenced regular expression.

If POSIX compliance is not important echo PARAM | can be replaced by <<<PARAM, reducing the functions length to 37:

f()([ ! `egrep '([0-9]).*\1'<<<$1` ])

Usage:

$ if f 48778584; then echo true; else echo false; fi
false
$ if f 17308459; then echo true; else echo false; fi
true

1 The fold -N notation is deprecated in some versions of fold.

Thor
fuente
f()(! [ `fold -1<<<$1|sort|uniq -d` ]) down to 38 by my count
Digital Trauma
@DigitalTrauma: Good stuff thanks for sharing. I find that the tested command must be quoted, otherwise test croaks on it when uniq -d returns more than one line. So the shortest non-POSIX version is 40 characters. I know about the [ ! notation, but I am suprised that ! [ also works, do you know why that is?
Thor
Ah I was using bash. So I guess its longer if you want POSIX conformance.
Digital Trauma
1

Java ( 131 59 57)

57 characters:

removed ^ and $ as @n̴̖̋h̷͉̃a̷̭̿h̸̡̅ẗ̵̨́d̷̰̀ĥ̷̳ suggested

boolean u(int n){return !(n+"").matches(".*(.).*\\1.*");}

59 characters (works also with negative numbers!):

boolean u(int n){return !(n+"").matches("^.*(.).*\\1.*$");}

79 78 characters (thanks @n̴̖̋h̷͉̃a̷̭̿h̸̡̅ẗ̵̨́d̷̰̀ĥ̷̳ ):

Use for loop to save a few charachers and use int as a boolean array.

Use & instead of && to save 1 character (It turns out that java allows it).

boolean u(int n){for(int x=0;n>0&(x>>n%10&1)==0;n/=10)x|=1<<n%10;return n==0;}

131 characters (returns true for negative numbers):

boolean u(int n){int[] p=new int[]{2,3,5,7,11,13,17,19,32,29};double a=9001312320D;while(n>0){a/=p[n%10];n/=10;}return (long)a==a;}

with comments:

boolean unique(int n){
    int[] p=new int[]{2,3,5,7,11,13,17,19,32,29};//list of 10 first primes
    double a=9001312320D;//10 first primes multiplied
    while(n>0){
        a/=p[n%10];//divide by (n%10+1)th prime
        n/=10;//divide n by 10, next digit
    }
    return (long)a==a;//if a is integer then n has all digits unique
}

And answer that is technically correct (character count includes only the function, not global variables), but I think it's cheating, 29 characters:

boolean u(int i){return m[i];}

m[] is boolean array that contains correct answers for all 32-bit integers.

barteks2x
fuente
"^.*(.).*\\1.*$" You can drop ^ and $. They are implied by matches()
n̴̖̋h̷͉̃a̷̭̿h̸̡̅ẗ̵̨́d̷̰̀ĥ̷̳
The 2nd approach can be done by using 10 bits in an int as a boolean array, which will eliminate the need for the prime table.
n̴̖̋h̷͉̃a̷̭̿h̸̡̅ẗ̵̨́d̷̰̀ĥ̷̳
I know it's been three years, but if you remove the space between return! in the shortest answer, you can get to 56 bytes.
Kevin Cruijssen