Permutations: Difference between revisions

=={{header|Langur}}==

{{trans|Go}}

<lang Langur>val .factorial = f if(.x < 2: 1; .x x self(.x - 1))

val .permute = f(.arr) {

if not isArray(.arr) {

throw "expected array"

}

val .limit = 10

if len(.arr) > .limit {

throw $"Permutation limit exceeded (currently \.limit;)"

}

var .size = .factorial(len .arr)

var .arrOf = [.arr]

var .elements = .arr

var .ordinals = series 1 .. len .elements

val .n = len(.ordinals)

var (.i, .j)

for .c = 1; .c < .size; .c += 1 {

.i = .n - 1

.j = .n

for .ordinals[.i] > .ordinals[.i+1] {

.i -= 1

}

for .ordinals[.j] < .ordinals[.i] {

.j -=1

}

(.ordinals[.i], .ordinals[.j]) = (.ordinals[.j], .ordinals[.i])

(.elements[.i], .elements[.j]) = (.elements[.j], .elements[.i])

.j = .n

.i += 1

for ; .i < .j; .i+=1, .j-=1 {

(.ordinals[.i], .ordinals[.j]) = (.ordinals[.j], .ordinals[.i])

(.elements[.i], .elements[.j]) = (.elements[.j], .elements[.i])

}

.arrOf = more .arrOf, .elements

}

return .arrOf

}

for .e in .permute([1, 3.14, 7]) {

writeln .e

}</lang>

{{out}}

<pre>[1, 3.14, 7]

[1, 7, 3.14]

[3.14, 1, 7]

[3.14, 7, 1]

[7, 1, 3.14]

[7, 3.14, 1]</pre>