Java/ Efficient way to find all permutation of lists -

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• cartesian product of arbitrary sets in java 9 answers
• generating possible permutations of list recursively 3 answers

i have list of lists in java: {{1,2},{3,4,5},{6,7,8}}

i try find permutations of list. meaning, in result list next: {{1,3,6},{1,3,7},{1,3,8},{1,4,6}....{2,5,8}}

there reasonable way it?

here list<list<integer> implementation.

static public void main(string[] argv) {         list<list<integer>> lst = new arraylist<list<integer>>();          lst.add(arrays.aslist(1, 2));         lst.add(arrays.aslist(3, 4, 5));         lst.add(arrays.aslist(6, 7, 8));          list<list<integer>> result = null;          result = cartesian(lst);          (list<integer> r : result) {             (integer : r) {                 system.out.print(i + " ");             }             system.out.println();         } }  static public list<list<integer>> cartesian(list<list<integer>> list) {     list<list<integer>> result = new arraylist<list<integer>>();     int numsets = list.size();     integer[] tmpresult = new integer[numsets];      cartesian(list, 0, tmpresult, result);      return result; }  static public void cartesian(list<list<integer>> list, int n, integer[] tmpresult, list<list<integer>> result) {     if (n == list.size()) {         result.add(new arraylist<integer>(arrays.aslist(tmpresult)));         return;     }      (integer : list.get(n)) {         tmpresult[n] = i;         cartesian(list, n + 1, tmpresult, result);     } }