Permutations: Difference between revisions
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[3,2,1]
yes</lang>
=={{header|OCaml}}==
<lang ocaml>(* Iterative, though loops are implemented as auxiliary recursive functions.
Translation of Ada version. *)
let next_perm p =
let n = Array.length p in
let i = let rec aux i =
if (i < 0) || (p.(i) < p.(i+1)) then i
else aux (i - 1) in aux (n - 2) in
let rec aux j k = if j < k then
let t = p.(j) in
p.(j) <- p.(k);
p.(k) <- t;
aux (j + 1) (k - 1)
else () in aux (i + 1) (n - 1);
if i < 0 then false else
let j = let rec aux j =
if p.(j) > p.(i) then j
else aux (j + 1) in aux (i + 1) in
let t = p.(i) in
p.(i) <- p.(j);
p.(j) <- t;
true;;
let print_perm p =
let n = Array.length p in
for i = 0 to n - 2 do
print_int p.(i);
print_string " "
done;
print_int p.(n - 1);
print_newline ();;
let print_all_perm n =
let p = Array.init n (function i -> i + 1) in
print_perm p;
while next_perm p do
print_perm p
done;;
print_all_perm 3;;
(* 1 2 3
1 3 2
2 1 3
2 3 1
3 1 2
3 2 1 *)</lang>
=={{header|PARI/GP}}==
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