Determine if all decimal digits are unique

Question

Deleted questions on Stack Overflow sometimes make for great golf material.

Write a function that takes a nonnegative integer as input, and returns true if all the digits in the base 10 representation of that number are unique. Example:

48778584 -> false
17308459 -> true

Character count includes only the function.

If you choose to answer in C or C++: no macros, no undefined behaviour; implementation-defined behaviour and compiler warnings are fine.

Answer 1

Zsh, 28 24 bytes

If output is 0, the digits are unique. Otherwise, there are dupes

<<<$[$#1-${#${(us::)1}}]

Try it Online! _{28 bytes}

Answer 2

Haskell, 32 bytes

(\s->s==[x|x<-s,y<-s,x==y]).show

Try it online!

Repeats each character once per each character that equals it, and checks that this gives the original digits string.

Answer 3

C 151

Bytes = 181 or 151 without newline chars. Program keeps a tally of digits and exits if greater than 1.

#include <stdio.h>
int i,j[10],r;
int main()
{
scanf("%d",&i);
do{
r=i%10;
j[r]++;
if(j[r]>1){printf("false");return 0;}
i/=10;
}while(i);
printf("true");
return 0;
}

Answer 4

C# 72 characters

var a=i.ToString().ToCharArray();
return a.Distinct().Count()==a.Count();

Answer 5

Julia, 44

f(n)=(d=digits(n);length(Set(d))==length(d))

Answer 6

Cobra - 109

def f(n) as bool
    l=0
    m=n.toString
    for i in m,for j in m,if i==j,l+=1
    return if(l>m.length,false,true)

Makes me wish that LINQ would work properly in Cobra.

Answer 7

C# 72 69 67 characters (no libraries needed)

for(;d>0;d/=10)for(int f=d/10;f>0;f/=10)if(d%10==f%10) return true;

Ungolfed:

for (; d > 0; d /= 10)
    for (int f = d / 10; f > 0; f /= 10) 
        if (d % 10 == f % 10) 
            return true;

I'm just using simple maths here.(i.e. number 1231):

• Take the last digit (1)
• Iterate through the quotient (123)
• If the number is equal to our digit (1), then return true
• 3 == 1, 2 == 1, 1 == 1 - found it!

Answer 8

Ruby(47 characters)

->(x){x.to_s.chars.sort.uniq.size==x.to_s.size}

Example usage

->(x){x.to_s.chars.sort.uniq.size==x.to_s.size}[10]
=> true

Answer 9

C# (44 - 64)

Func

As a lambda (44):

y=>!(y+"").GroupBy(x=>x).Any(x=>x.Count()>1)

alt lambda (also 44):

y=>(y+"").GroupBy(x=>x).All(x=>x.Count()==1)

As a Func (63):

Func<int, bool> f=y=>(y+"").GroupBy(x=>x).All(x=>x.Count()==1);

As a method (64):

bool f(int y){return (y+"").GroupBy(x=>x).All(x=>x.Count()==1);}

Answer 10

Extended BrainFuck: 100

not included the unnecessary linefeed.

{a>[>>]}>>,10-[38-[-&a+[<<]>]&a>[[-]3<[-<<]<+2>&a>]
+3<[-<<]>,10-]<+<([-]>-|"false"[-])>(-|"true"[-])

Usage:

%> beef ebf.bf < unqiue.ebf > unqiue.bf
%> echo 48778584 | beef unique.bf 
-> false
%> echo 17308459 | beef unique.bf 
-> true

Answer 11

VBA (145)

Function jkl(f As String) As Boolean
For i = 1 To Len(f)
jkl = InStr(1, f, Left(Mid(f, i), 1)) <> i
If jkl = True Then Exit Function
Next
End Function

Calling the function and output with opposite of the result:

Sub jj()
Dim f As String
f = "1234256789"
MsgBox Not (jkl(f))
End Sub

Answer 12

PHP 74 Chars

<?php $a=str_split($argv[1]);var_dump(count($a)==count(array_unique($a)));

Answer 13

VB.NET - 189 184

Function U(I As Integer) As Boolean
    U = True
    Dim D(9)
    Dim S = I.ToString
    For Each E As Char In S
        If IsNumeric(E) Then If D(Val(E)) + 1 > 1 Then U = False Else D(Val(E)) += 1
    Next
End Function

First code-golf attempt. I'm aware it's an unsuitable language and poor result, but I wanted to try.

Answer 14

Clojure - (42 - 52)

As a named function (52):

(defn f[i](let[s(str i)](=(count s)(count(set s)))))

As an anonymous function (42):

#(let[s(str %)](=(count s)(count(set s))))

Answer 15

Scala

Cheating with library functions (29/12 characters):

def t(i:String)=i==i.distinct

Scala version of the GolfScript version (36/19 characters):

def t(i:String)=i.intersect(i).size>0

Doing the counting work manually (91/74 characters):

def t(i:String)=(Map.empty[Char,Int]/:i)((m,c)=>m+(c->(m.getOrElse(c,0)+1))).forall(_._2<2)

Answer 16

PHP - 44 33

var_dump(max(count_chars($n))<2);

Or Proper function 42 Characters

function(){return max(count_chars($n))<2;}

UPDATE : Thanks for @scrblnrd3 pointed out for shorter solution.

Answer 17

Haskell (41)

import Data.List
f x=show x==nub(show x)

About 23 characters shorter than the other Haskell answer and a fair bit more intuitive I think. Basically the same process but using Haskell's built-in list functions is much easier and shorter.

Answer 18

C - 62

int m[10];f(int a){while(m[a%10]++?0:a/=10);return m[a%10]<2;}

I've included the count of the globally declared array (which ensures initialisation to 0).

As a bonus, here is a much shorter technically correct answer:

f(int a){return 1}

The question does not state that non-unique digits should return false. Therefore I claim the current lead for C code with 18 characters, although I expect to be beaten by a scripting language with an answer like:

1

Answer 19

Julia - 29 28

f(n)=unique("$n")=="$n".data

Old version:

f(n)=join(unique("$n"))=="$n"

Answer 20

F# - 82

let f i =
    let s = i.ToString() 
    s |> Set.ofSeq|> Seq.length = s.Length;;

Answer 21

COBOL 66 with Object Cobol extensions

Microfocus Cobol (721 659 592)

       method-id u.
       local-storage section.
       77  i pic s9(9) comp.
       77  c pic 9 occurs 10 value 0.
       77  g pic 9.
       01  s pic 9(9).
       01  t redefines s pic 9 occurs 9.
       linkage section.
       77  n pic s9(9) comp.
       77  d pic x.
       88  f value is 'y'.
       procedure division using by value n returning d.
           move n to s. move 'n' to d. perform p varying i from 1 by 1 until i greater than 9 or f. goback.
       p.  move t (i) to g. if c (g) is not zero then move 'y' to d. add 1 to c (g).
       end method.

Hmmm, I think I should go back to pitch & putt :(

EDIT: OMGZ I CAN USE LOWER CASE!!!

Answer 22

C++ 82

this code is at least legitimate

int a(uint32_t i,uint32_t r=0,uint32_t h=0)
{return i?r&h?0:a(i/10,r|h,1<<i%10):1;}        // thanks to DreamWarrior

C 47

this works if you compile it in debug mode or provide two more arguments set to 0

a(i,r,h){return i?r&h?0:a(i/10,r|h,1<<i%10):1;}

Answer 23

Regular Expression 17 bytes

^(?:(.)(?!.*\1))*$

Original expression taken from https://stackoverflow.com/a/12870549.

Answer 24

Clojure, 23

#(=(distinct x)(seq x))

Usage: (#(=(distinct x)(seq x)) "23563462464543")

Answer 25

Candy, 13 bytes

This is a late post, but...

(k&{1k1.|0})0

Invokation with -I , which is actually for string parameters.

The long form:

while    # while we are still consuming characters from the stack
  setSP  # pop the next stack-id from the stack.  It's the ord of the digit
  stackSz  # test for empty stack
  if
    digit1 setSP  # goto stack #1, and push the true indicator on
    digit1
    retSub        # and halt
  else
    digit0    # mark the stack as having been visited
  endif
endwhile
digit0    # push the false indicator if we got this far

Answer 26

Prolog, 49 bytes

Code:

p(N):-number_codes(N,L),sort(L,S),msort(L,T),S=T.

Explained:

p(N):-number_codes(N,L), % Convert int to list (of charcodes)
      sort(L,S),         % Sort list and remove duplicates
      msort(L,T),        % Sort list and keep duplicates
      S=T.               % Check if lists are equal

Example:

p(48778584).
false

p(17308459).
true

Answer 27

05AB1E, 2 bytes

ÙQ

Try it online!

-1 thanks to Kaldo

---

{   # Sort.
 ¥  # Consecutive differences.
  P # Product.

---

Works on negatives, though OP never specified...

Answer 28

rSNBATWPL, 45 bytes

n~(d=1;rdc{norm{n}sort<}$a~b~(d=d*a!b;b);d)

A (probably golfable) approach, which looks for duplicate characters. Instead of a costly cast.string, I use norm, which applies Unicode normalization, which is a no-op here. I use rdc as an expensive hack to iterate over pairs. The most important part of the solution is d=d*a!b (I use d=d*... rather than d*=... since *= requires whitespace to prevent ambiguity), which multiplies d (initially 1) by a!b, which after being cast to an int will be 1 only if a and b aren't equal.

Answer 29

Thunno 2, 2 bytes

U=

Attempt This Online!

Explanation

U=  # Implicit input
U   # Uniquify the input
 =  # Does it equal the input?
    # Implicit output

Answer 30

Pascal, 142 bytes

This function requires a processor compliant with Extended Pascal, ISO standard 10206. In particular the card function must be available.

function f(x:integer):Boolean;var d:set of 0..9;w:integer;begin d:=[];w:=0;repeat d:=d+[x mod 10];x:=x div 10;w:=w+1 until x=0;f:=w=card(d)end

Ungolfed:

    type
        { This will permit a proper `function` domain restriction. }
        integerNonNegative = 0..maxInt;
    
    { Returns `true` if `x` as decimal number contains no duplicate digits. }
    function hasUniqueDecimalDigits(x: integerNonNegative): Boolean;
        var
            { The decimal digits that appear in `x`. }
            digits: set of 0‥9 value [];
            { The total width of a decimal representation of `x`. }
            width:  integer    value 0;
        begin
            { If there are as many distinct decimal `digits` as
              the total `width` of the decimal number,
              we can tell that no digit appears twice. }
            repeat
            begin
                digits ≔ digits + [x mod 10];
                x      ≔ x div 10;
                width  ≔ width + 1;
            end
            until x = 0;
            { `card` returns the cardinalty of a set,
              that is the number of members in a set. }
            hasUniqueDecimalDigits ≔ card(digits) = width;
        end;