Diberikan array bilangan bulat positif dan dua indeks valid berbeda, kembalikan array dengan dua elemen yang sesuai dengan dua indeks yang ditukar.

Anda dapat memilih untuk menggunakan pengindeksan 0 atau pengindeksan 1, tetapi testcases di bawah ini akan diindeks 0.

array        m n output
[1,2,3,4]    0 1 [2,1,3,4]
[5,8,9]      0 2 [9,8,5]
[11,13,15,3] 1 2 [11,15,13,3]
[11,13,15,3] 2 1 [11,15,13,3]
[11,15,15,3] 2 1 [11,15,15,3]

Ini adalah kode-golf . Jawaban terpendek dalam byte menang. Celah standar berlaku.

C/ C ++, 53 50 39 byte

f(a,m,n)int*a;{a[m]^=a[n]^=a[m]^=a[n];}

Cobalah online

Disimpan 11 byte berkat @Dennis

Pengoperasian Bahasa skrip Flashpoint , 98 95 byte

f={t=_this;a=t select 0;b=+a;m=t select 1;n=t select 2;a set[m,b select n];a set[n,b select m]}

Memodifikasi array secara langsung.

Penjelasan:

t=_this;                   // Give a shorter name for the array of arguments.

a=t select 0;              // Let 'a' be a pointer to the array that we modify.
                           // (The language doesn't have a concept of pointers really,
                           // yet its array variables are pointers to the actual array.)

b=+a;                      // Make a copy of the original array and save a pointer to it
                           // in the variable 'b'. This saves a few bytes later.

m=t select 1;              // Read the index arguments from the input array and save them
n=t select 2;              // to their respective variables.

a set[m,b select n];       // Do the swapping by reading the values from the copy and
a set[n,b select m]        // writing them to the original array. The last semicolon can
                           // be omitted because there are no more statements following 
                           // the last statement.

Telepon dengan:

array = [1,2,3,4];
str = format["%1", array];
[array, 0, 1] call f;
hint format["%1\n%2", str, array];

Keluaran:

JavaScript ES6, 36 32 byte

Lihat, Bu, tidak ada variabel sementara!

(a,m,n)=>[a[m],a[n]]=[a[n],a[m]]

• 4 byte disimpan berkat Neil membawa konsensus ini menjadi perhatian saya.

Cobalah

Masukkan daftar elemen yang dipisahkan koma untuk adan 2 bilangan bulat untuk m& n.

f=
(a,m,n)=>[a[m],a[n]]=[a[n],a[m]]
oninput=_=>o.innerText=(f(b=i.value.split`,`,+j.value,+k.value),b);o.innerText=(f(b=(i.value="5,8,9").split`,`,j.value=0,k.value=2),b)

*{font-family:sans-serif}input{margin:0 5px 0 0;width:100px;}#j,#k{width:50px;}

<label for=i>a: </label><input id=i><label for=j>m: </label><input id=j type=number><label for=k>n: </label><input id=k type=number><pre id=o>

Python 3 , 41 32 byte

-9 byte terima kasih kepada @notjagan

def f(a,m,n):a[m],a[n]=a[n],a[m]

Cobalah online!

Mengubah argumennya, yang merupakan format output yang valid .

Jelly , 7 byte

Ṛ,ḷyJ}ị

Cobalah online!

Bagaimana itu bekerja

Ṛ,ḷyJ}ị  Main link. Left argument: [i, j]. Right argument: A (array)

Ṛ        Reverse; yield [j, i].
  ḷ      Left; yield [i, j].
 ,       Pair; yield [[j, i], [i, j]].
    J}   Indices right; yield all indices of A.
   y     Transliterate; replace j with i and i with j.
      ị  Index into A.

Japt , 17 16 byte

hV(A=UgV UgW¹hWA

Cobalah online!

Disimpan satu byte berkat produk ETH

MATL , 7 6 byte

yyP)w(

Indeks berbasis 1.

Cobalah online!

Penjelasan

Pertimbangkan input [11 13 15 3], [2 3].

yy   % Take two inputs implicitly. Duplicate them
     % STACK: [11 13 15 3], [2 3], [11 13 15 3], [2 3]
P    % Flip
     % STACK: [11 13 15 3], [2 3], [11 13 15 3], [3 2]
)    % Reference indexing (pick indexed entries)
     % STACK: [11 13 15 3], [2 3], [15 13]
w    % Swap
     % STACK: [11 13 15 3], [15 13], [2 3]
(    % Assignment indexing (write values into indexed entries). Implicitly display
     % STACK: [11 15 13 3]

C # (.NET Core) , 48 43 31 byte

(a,m,n)=>a[m]+=a[n]-(a[n]=a[m])

Cobalah online!

Tukar angka dalam array asli, tidak ada variabel sementara yang digunakan. Meskipun demikian saya tidak dapat menerima pujian atas jawaban ini karena sudah menjadi ide Neil .

Gangguan Umum , 42 byte

-2 byte berkat @coredump .

(lambda(a i j)(rotatef(elt a i)(elt a j)))

Cobalah online!

Cukup lurus ke depan, karena ada makro Common Lisp untuk swap: rotatef.

Javascript ES6, 36 34 byte

(a,m,n)=>(x=a[m],a[m]=a[n],a[n]=x)

• -2 Bytes karena fungsinya mengubah array. Tidak perlu mengembalikan array. Terima kasih kepada @Neil

Demo

f=

(a,m,n)=>(x=a[m],a[m]=a[n],a[n]=x)

let a1=[1,2,3,4], a2=[5,8,9], a3=[11,13,15,3]

f(a1,0,1);
f(a2,0,2);
f(a3,1,2);

console.log(JSON.stringify(a1)); //[2,1,3,4]
console.log(JSON.stringify(a2)); //[9,8,5]
console.log(JSON.stringify(a3)); //[11,15,13,3]

CJam , 4 byte

{e\}

Cobalah online!

Java 8 , 48 byte

(a,b,c)->{int t=a[b];a[b]=a[c];a[c]=t;return a;}

Memasukkan:

int[] a
int b
int c

05AB1E , 10 byte

D²è³ǝ¹³è²ǝ

Cobalah online!

Oktaf , 28 byte

@(a,n){a(n)=a(flip(n)),a}{2}

Cobalah online!

Cukup puas dengan yang satu ini sebenarnya :)

Mengambil input pada formulir f([1,2,3,4],[1,2]):, 1-diindeks.

Penjelasan:

@(a,n)                         % Anonymous function that takes two 1-dimensional
                               % arrays as input
      {               , }      % Create a cell with two elements
       a(n)=a(flip(n))         % One element are the two number at indices given by
                               % the second input array. This will be a 1x2 array
      {a(n)=a(flip(n)),a}      % Place those two in a cell together with the entire array a
                               % a is now updated, thanks to Octave's inline assignment
      {a(n)=a(flip(n)),a}{2}   % Return the second element

Jellyfish, 7 bytes

p
ZRi
i

Takes a list and a pair of indices. Try it online!

Explanation

Jellyfish happens to have a "modify items at indices" function, Z, which does exactly what we need. The two is grab the inputs from STDIN. Z takes as arguments the second input, the reversal function R, and the list. Then Z performs the modification, and p prints the result.

R, 38 bytes

function(x,a,b){x[c(a,b)]=x[c(b,a)];x}

Feels rather long, but I can't get it much shorter. Sadly it requires the explicit returning through x, requiring {} around the function body. pryr::f() doesn't recognise the need for x as function argument so doesn't work :/.

Shenzhen I / O, 735 Bytes

23 ¥, 810 Kekuatan, 48 Baris Kode

[traces] 
......................
......................
......................
......................
......................
......................
.14.14.14.............
.94.14.14.............
.A........1C..........
.3554..95556..........
.9554.16..............
.A....................
.2....................
......................

[chip] 
[type] UC6
[x] 4
[y] 2
[code] 
  slx x0
  mov x1 acc
  mov x1 dat
  mov acc x3
  mov dat x3
  mov acc x3
  mov dat x3

[chip] 
[type] UC6
[x] 8
[y] 5
[code] 
  slx x2
  mov x2 x1
  mov x0 dat
  mov x2 x1
  mov x0 acc
  mov x2 x1
  mov dat 

[chip] 
[type] UC4X
[x] 2
[y] 6
[code] 
  slx x0
  mov 0 x3
j:  mov x0 acc
  mov acc x2
  teq acc 0
- jmp j
  mov -999 x1

[chip] 
[type] RAM
[x] 5
[y] 6

PENOLAKAN: Array diakhiri 0 dalam hal ini. Array adalah rasa sakit di pantat untuk bekerja dengan di Shenzhen I / O sebaliknya.

Saya sebenarnya membuat level uap untuk game ini. Anda bisa memainkannya di sini.

EDIT: Aaand saya baru sadar saya mengatakan bahwa array di diperintahkan. Heck.

Swift, 111 65 byte (0-diindeks)

Swift is already notorious for being one of the worst code-golf languages, but here is a function that makes use of ternary expressions:

func t(l:[Int],m:Int,n:Int){var r=l;r[m]=l[n];r[n]=l[m];print(r)}

Check it out! - Usage: t(l:[1,2,3],m:0,n:1).

k (kona), 13 bytes

{x[y]:x@|y;x}

Pretty basic, but it works. Ex:

k){x[y]:x@|y;x}[1 2 3 4; 0 1]
2 1 3 4

Perl 5, 32 bytes

-3 bytes thanks to @Dom Hastings!

30 bytes of code + -pa flags.

@F[pop@p,@p]=@F[@p=<>];$_="@F"

Try it online!

Quite straight forward, using array slices.

Mathematica, 32 bytes

(a=#;a[[{##2}]]=a[[{#3,#2}]];a)&

C, 42 bytes

Modify the array in place with a temp value.

f(r,m,n){int*a=r;r=a[m];a[m]=a[n];a[n]=r;}

C, 60 58 bytes

A little more interesting, not using any temp value...

f(a,m,n)int*a;{a[m]+=a[n];a[n]-=a[m];a[n]*=-1;a[m]-=a[n];}

C, 49 bytes

Using XOR

f(a,m,n)int*a;{a[m]^=a[n];a[n]^=a[m];a[m]^=a[n];}

Pyth, 17 8 bytes

Saved 9 bytes thanks to Leaky Num.

@LQ.rUQE

Test it online!

This is 0-indexed, and the indices are provided as a tuple: (n, m).

Explanations

@LQ.rUQE

     UQ     # Generate [0, 1, 2, ..., len(input)]
       E    # Get the indices as the tuple (1, 2)
   .r       # Translate each element of UQ to its cyclic successor in E
            # Now the indices are permuted (e.g. [0, 2, 1, ..., len(input)]
@LQ         # For each index, get it's value. Implicit print

Mathematica, 20 bytes

#~Permute~Cycles@#2&

Pure function taking two arguments in the following 1-indexed (and possibly abusive) format: the second test case [5,8,9]; 0 2; [9,8,5] would be called as

#~Permute~Cycles@#2& [ {5,8,9} , {{1,3}} ]

(spaces are extraneous and just for visible parsing). Permute is the builtin function that applies a permutation to a list, and Cycles[{{a,b}}] represents the permutation that exchanges the ath and bth elements of a list and ignores the rest.

x86 Machine Code, 10 bytes

8B 04 8B 87 04 93 89 04 8B C3

This is a function written in 32-bit x86 machine code that swaps the values at the specified indices in a given array. The array is modified in-place, and the function does not return a value.

A custom calling convention is used, requiring the function's parameters to be passed in registers:

• The address of the array (pointer to its first element) is passed in the EBX register.
• Indeks elemen A berbasis nol dilewatkan dalam ECXregister.
  _{(Diasumsikan sebagai indeks yang valid.)}
• Indeks elemen B berbasis nol dilewatkan dalam EDXregister.
  _{(Diasumsikan sebagai indeks yang valid.)}

Ini menjaga ukurannya turun dan mematuhi semua persyaratan formal, tetapi berarti bahwa fungsi tersebut tidak dapat dengan mudah dipanggil dari bahasa lain seperti C. Anda harus memanggilnya dari program bahasa assembly lainnya. (Anda dapat menulis ulang untuk menggunakan register input apa pun , tanpa mempengaruhi jumlah byte; tidak ada yang ajaib tentang yang saya pilih.)

Tidak Disatukan:

8B 04 8B     mov  eax, DWORD PTR [ebx+ecx*4]   ; get value of element A
87 04 93     xchg eax, DWORD PTR [ebx+edx*4]   ; swap element A and element B
89 04 8B     mov  DWORD PTR [ebx+ecx*4], eax   ; store new value for element A
C3           ret                               ; return, with array modified in-place

R, 34 bytes

pryr::f(`[<-`(a,c(m,n),a[c(n,m)]))

Java 8 + InverseY, 27 bytes

java.util.Collections::swap

Just calls the swap function... this is a method reference of the type Consumer3<List, Integer, Integer>.

Try it online! (header and footer for boilerplate & copy of Consumer3 interface)

JavaScript (ES2015), 66 57 49 bytes

A different (alas, longer) approach than previous JavaScript answers

(s,h,o,w=s.splice.bind(s))=>w(h,1,...w(o,1,s[h]))

Source

const swap = (arr, a, b, splice) => {
  splice(a, 1, ...splice(arr[b], 1, arr[a]))
}

awk, 31 bytes

{c=$a;$a=$b;$b=c;a=$1;b=$2}NR>1

Try it online!

Takes input in the format

1 2
1 2 3 4

and outputs as

2 1 3 4

(1-indexed).

Explanation

The entire program is a missing pattern with an action followed by a pattern with a missing action.

Since a missing pattern runs on each line, the code inside the braces runs for both input lines. The c=$a;$a=$b;$b=c; part swaps the two values at indices a and b (through the temporary variable c). This only has an effect on the second line, since on the first line a and b are not yet defined. The a=$1;b=$2 part defines a to be the first field and b to be the second field, which sets the appropriate values for the first part to run on the second line.

Since a missing action is equivalent to {print}, the pattern prints every line it matches. This pattern in particular is NR>1: that is, print whenever the line number is greater than 1, which happens to be line 2. This runs after the swapping of values has taken place, thus completing the task.

q/kdb+, 17 bytes

Solution:

{@[x;(|)y;:;x y]}

Example:

q){@[x;(|)y;:;x y]}[1 2 3 4;0 1]
2 1 3 4

Explanation:

A q version of the k answer by Simon. Apply the assign : function to x at indices reverse-y with value of x indexed at y. Broken down you can see more clearly:

q)x:1 2 3 4
q)y:0 1
q)x y
1 2
q)(|)y
1 0
q)x(|)y
2 1
q)@[x;(|)y;:;x y]
2 1 3 4