1 | static <A> IterableIterator<L<A>> allPermutations_iterator(L<A> theList) {
|
2 | ret iteratorFromFunction(new F0<A> {
|
3 | L<A> list = cloneList(theList); |
4 | int[] stack = new int[l(theList)+1]; |
5 | int n = l(theList); |
6 | |
7 | A get() {
|
8 | findNext(); |
9 | if (n <= 1) {
|
10 | ++n; // return from subroutine |
11 | ret cloneList(list); |
12 | } else if (stack[n] < n) |
13 | ++stack[n]; |
14 | } |
15 | L<A> l = cloneList(list); |
16 | |
17 | if (stackPtr[n] < n) |
18 | ++stackPtr[n]; |
19 | ret l; |
20 | } |
21 | }; |
22 | new LL<A> out; |
23 | allPermutations_impl(cloneList(l), l(l), out); |
24 | ret out; |
25 | } |
26 | |
27 | static <A> void allPermutations_impl(L<A> l, int n, LL<A> out) {
|
28 | if (n <= 1) {
|
29 | ping(); |
30 | out.add(cloneList(l)); |
31 | } else for(int i = 0; i < n; i++) {
|
32 | allPermutations_impl(l, n-1, out); |
33 | swapElements(l, n % 2 == 0 ? i : 0, n-1); |
34 | } |
35 | } |
Began life as a copy of #1010320
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| Snippet ID: | #1010342 |
| Snippet name: | allPermutations_iterator - return all permutations of a list as iterator [old] |
| Eternal ID of this version: | #1010342/3 |
| Text MD5: | aba1fc9712d08f2fb8507c2e8f7e2f63 |
| Author: | stefan |
| Category: | javax |
| Type: | JavaX fragment (include) |
| Public (visible to everyone): | Yes |
| Archived (hidden from active list): | Yes |
| Created/modified: | 2019-07-15 02:25:32 |
| Source code size: | 874 bytes / 35 lines |
| Pitched / IR pitched: | No / No |
| Views / Downloads: | 391 / 395 |
| Version history: | 2 change(s) |
| Referenced in: | [show references] |