I wrote some library to make combination in 2013.

I think that finding combination isn't necessarily written using recursive calling.
so this is my first "working" solution.

it is possible to use some list of words (ex) "a", "b", "c" ) instead of number.

#!/usr/bin/env perl
# -*- Mode: cperl; cperl-indent-level:4; tab-width: 8; indent-tabs-mode: nil -*-
# Copyright (c) 2013,2020 JEON Myoungjin 

use strict; use warnings;

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