Find the minimum and maximum integers in an array, without using builtins

Question

Challenge

Given an array of integers, received from stdin, function arguments, program arguments, or some other method:

Output only the minimum and maximum numbers in the array, through a return value, stdout, or other fitting methods.

Example session

> minmax( {0, 15, 2, 3, 7, 18, -2, 9, 6, -5, 3, 8, 9, -14} )
-14 18

Reference implementation

// C++14

void minmax(std::vector<int> v) {
    int min = v[0]; int max = v[0];
    for(auto it : v) {
        if (*it < min)
            min = *it;
        if (*it > max)
            max = *it;
    }
    std::cout << min << ' ' << max << std::endl;
}

Rules

• You may not use a built-in function to calculate the values.
• Standard loopholes disallowed.
• Creative implementations encouraged.
• This is code-golf, shortest answer wins but will not be selected.

Clarifications

• If the array contains 1 element you need to output it twice.
• If the minimum and maximum values are the same, you need to output them both.

Answer 1

Jelly, 3 bytes

Ṣ.ị

Try it online!

Sort the array, and then takes the 0.5-th element.

Jelly uses 1-indexing, and floating points indexing means take its floor and its ceil.

So the 0.5-th element would give you the 0th element and the 1st element.

The 0th element is the last element.

Answer 2

Python, 61 49 37 36 34 31 bytes

lambda s:s.sort()or[s[0],s[-1]]

-12 bytes thanks to RootTwo

Another -12 bytes thanks to chepner

-2 bytes thanks to johnLate

-3 bytes thanks to johnLate

Answer 3

Brain-Flak 220 218 bytes

(({}))([]){({}[()]<(([])<{({}[()]<([([({}<(({})<>)<>>)<><({}<>)>]{}<(())>)](<>)){({}())<>}{}({}<><{}{}>){{}<>(<({}<({}<>)<>>)<>({}<>)>)}{}({}<>)<>>)}{}<>{}>[()]){({}[()]<({}<>)<>>)}{}<>>)}{}({}<((())){{}{}([][()])}{}>)

Try It Online!

Explanation

First it doubles the top value (in cast the list is only one long)

(({}))

Then it uses my bubble sort algorithm:

([]){({}[()]<(([])<{({}[()]<([([({}<(({})<>)<>>)<><({}<>)>]{}<(())>)](<>)){({}())<>}{}({}<><{}{}>){{}<>(<({}<({}<>)<>>)<>({}<>)>)}{}({}<>)<>>)}{}<>{}>[()]){({}[()]<({}<>)<>>)}{}<>>)}{}

Then it picks up the top value of the stack (i.e. the min)

({}<...>)

Then it pops until the height of the stack is one:

((())){{}{}([][()])}{}

Answer 4

JavaScript (ES6), 34 bytes

a=>[a.sort((x,y)=>x-y)[0],a.pop()]

sort sorts in-place, so I can just refer to the [0] index for the lowest value and pop the highest value from the array, however it does a string sort by default so I have to pass a comparator.

Answer 5

Mathematica, 18 bytes

Sort[#][[{1,-1}]]&

Sorts the array and extracts the first and last values.

Answer 6

R, 31 bytes

l=sort(scan());l[c(1,sum(l|1))]

Not that original, but hey !

Answer 7

ARM Machine Code, 26 bytes

Hex dump (little endian):

6810 4601 f852 cb04 4560 bfc8 4660 4561 bfb8 4661 3b01 d8f5 4770

This is a function, with no system call or library dependence. The encoding is Thumb-2, a variable (2 or 4 byte) encoding for 32-bit ARM. As one might imagine, there's no easy way to just sort and pick the first and last elements here. Overall there's nothing really that fancy going on here, it's more or less the same as the reference implementation.

Ungolfed assembly (GNU syntax):

.syntax unified
.text
.global minmax
.thumb_func
minmax:
    @Input: @r0 and r1 are dummy parameters (they don't do anything)
    @r2 - Pointer to list of integers (int*)
    @r3 - Number of integers to sort (size_t)
    @Output:
    @Minimum of the list in r0 (int)
    @Maximum in r1 (int)
    ldr r0,[r2] @min=r2[0]
    mov r1,r0 @max=min
    loop:
        @ip is intra-procedure call register, a.k.a. r12
        ldr ip,[r2],#4 @ip=*r2++
        cmp r0,ip
        it gt @if (r0>ip)
        movgt r0,ip @r0=ip
        cmp r1,ip
        it lt @if (r1<ip)
        movlt r1,ip @r1=ip
        subs r3,r3,#1
        bhi loop @while (--r3>0)
    bx lr @Return

Tested on the Raspberry Pi 3; here's the testing script (C99, input through argv):

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
//First 2 arguments are dummies.
uint64_t minmax(int,int,int* array,size_t size);

int main(int argc,char** argv) {
    int i;
    int array[argc-1];
    for (i=1;i<argc;i++) {
        array[i-1]=atoi(argv[i]);
    }
    uint64_t result = minmax(0,0,array,argc-1);
    printf("Minimum is %d, maximum is %d.\n",(unsigned)result,(unsigned)(result>>32));
}

Answer 8

Haskell, 27 bytes

f x=(`foldl1`x)<$>[min,max]

In Haskell, min and max give minimum and maximum of two arguments, not of a list. I couldn't tell whether this is disallowed (it seems that instead only minimum and maximum would be disallowed) so please let me know if they are and I'll promptly delete this answer.

Answer 9

Octave, 20 bytes

@(n)sort(n)([1,end])

This sorts the input vector and outputs the first and last value.

Answer 10

Actually, 5 bytes

S;F@N

Try it online!

Explanation:

S;F@N
S      sort
 ;     dupe
  F    first element
   @N  and last element

Answer 11

05AB1E, 6 4 bytes

{Âø¬

Explanation

{     # sort list
 Â    # bifurcate
  ø   # zip
   ¬  # head

Try it online

Answer 12

MATL, 4 bytes

S5L)

Try it online!

Explanation

S    % Implicitly input the array. Sort
5L   % Push [1 0]. When used as a (modular, 1-based) index, this means "first and last"
)    % Apply as an indexing vector into the sorted array. Implicitly display

Answer 13

Python, 29 bytes

lambda s:s[s.sort():1]+s[-1:]

Test it on Ideone.

Answer 14

C, 83 81 79 bytes

m,M;f(a,s)int*a;{for(m=M=*a;s--;++a)*a<m?m=*a:*a>M?M=*a:0;pr‌​intf("%i %i",m,M);}

Answer 15

Brachylog, 9 bytes

oOtT,Oh:T

Try it online!

Answer 16

V, 12 bytes

:sor
ò2Gjkd

Try it online!

Credit to DJMcMayhem for this.

Answer 17

CJam, 10 9 bytes

q~$_(p;W>

Try it online.

I'm really not good at CJam.

q~          e# eval input
  $         e# sort
   _        e# duplicate
    (       e# pop first
     p      e# print
      ;     e# remove array
       W>   e# get last element

Answer 18

Perl 6 13 bytes

*.sort[0,*-1]

Test:

my &min-max = *.sort[0,*-1];

say min-max 1;
# (1 1)
say min-max (0, 15, 2, 3, 7, 18, -2, 9, 6, -5, 3, 8, 9, -14)
# (-14 18)

Answer 19

Python 2, 34 bytes

x=sorted(input());print x[0],x[-1]

Answer 20

PHP, 44 bytes

function a($a){sort($a);echo $a[0].end($a);}

Answer 21

POSIX Awk, 44 bytes

awk '{for(;NF-1;NF--)if($1>$NF)$1=$NF}1' RS=

Answer 22

Java, 115 bytes

String f(int[]i){int t=i[0],a=t,b=t;for(int c=0;c<i.length;c++){a=i[c]<a?i[c]:a;b=i[c]>b?i[c]:b;}return""+a+" "+b;}

Ungolfed:

String f(int[] i) {
    int t=i[0], a=t, b=t; // assigns a and b to i[0]
    for (int c=0; c < i.length; c++) { // loop through the array
        a=(i[c]<a) ? i[c] : a;
        b=(i[c]>b) ? i[c] : b; // assignment with ternary operator
    }
    return ""+a+" "+b; // returns a string
}

My first ever code "golf" solution.

Answer 23

JavaScript (ES6), 46 bytes

I wanted to try an answer without sorting:

a=>a.map(i=>i<n?n=i:i>x?x=i:0,n=x=a[0])&&[n,x]

Bonus recursive version, 53 bytes:

f=([i,...a],n=i,x=i)=>i+.5?f(a,i<n?i:n,i>x?i:x):[n,x]

Answer 24

JavaScript (ES6), 68 58 bytes (without sorting)

Oh my first try in Golf: without explicit sort (and without min max).
Thanks to @ETHproductions for golfing tips!!

a=>(b=[],a.map(n=>b[n]=0),[b.indexOf(0),b.lastIndexOf(0)])

Does not work with negative integers.

Tried @Luis Mendo 's approach but got it 2 bytes longer... Cost for supporting negative numbers lol?

a=>[a.find(n=>a.every(e=>e>=n)),a.find(n=>a.every(e=>e<=n))]

Could get shorter if order of output is not important:

a=>a.filter(n=>a.every(e=>e>=n)||a.every(e=>e<=n))

Answer 25

Processing, 59 52 bytes

void m(int[]x){x=sort(x);print(x[0],x[x.length-1]);}

Processing doesn't actually let me read from stdin that I've been able to find, and I don't know if its internal Java compiler supports lambdas (and its been so long since I've had to write serious Java that I don't remember how).

Answer 26

PHP, 66 65 bytes

Note: this doesn't use any sort builtin. Also, PHP 7 required for the null coalesce operator.

for(;n|$x=$argv[++$i];$x>$h&&$h=$x)$l=min($l??$x,$x);echo"$l,$h";

The max part is straightforward. The min part is a bit more elaborate. since in PHP null is less than 123, null needs to be handled. For this I'm using the null coalesce operator. If $l is null, use the current number ($x) instead, then take the smaller of the 2 numbers.

Run like this:

php -d error_reporting=30709 -r 'for(;n|$x=$argv[++$i];$x>$h&&$h=$x)$l=min($l??$x,$x);echo"$l,$h";' -- 0 15 2 3 7 18 -2 9 6 -5 3 8 9 -14;echo

37 bytes (with sort)

Being allowed to sort makes it trivial (windows-1252 encoding):

php -d error_reporting=30709 -r '$a=$argv;echo$a[sort($a)],~ß,end($a);' -- 0 15 2 3 7 18 -2 9 6 -5 3 8 9 -14;echo

Sort returns 1 when successful, and the list of arguments will start with - which will be sorted as the first item, so we need item 1 to yield min. Therefore we happen to be able to use the return value of sort as the index, saving 2 bytes.

Tweaks

• Use n|"0" to make "0" truthy to continue the loop, instead of 0 ."0". Saved a byte

Answer 27

APL (Dyalog), 11 10 5 bytes

-5 thanks to Erik the Outgolfer.

According to the original poster, using a function that picks the largest of exactly two elements (in contrast to the largest of a whole array) [is] allowed. Therefore, the obvious solution is:

⌊/,⌈/

⌊/ minimum-reduction

, followed by

⌈/ maximum-reduction

---

More in the spirit of the challenge:

(⊃,⊢/)⍋⊃¨⊂

(

 ⊃ first

 , followed by

 ⊢/ the last (lit. right-reduction)

) of

⍋ the indices of the elements in ascending order

⊃¨ each picks from

⊂ the entire argument

TryAPL online!

Answer 28

Julia 0.6, 19 bytes

x->sort(x)[[1,end]]

Try it online!

Answer 29

C++ (g++), 148 133 131 122 119 bytes

#import<map>
#import<vector>
[](std::vector<int>v){int a=v[0],b=a;for(int i:v)i<a?a=i:i<b?:b=i;printf("%d %d\n",a,b);};

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Answer 30

Haskell, 36 bytes

(\l->(head l,last l)).Data.List.sort

Would love to use &&& here but imports are so costly...