reverse stack recursively at O(n) time and O(n) space. reimplementation of http://www.zhihu.com/question/24020049/answer/26440695

reverse.pl

#!/usr/bin/env perl

use strict;
use warnings;

sub rev {
    my $q = pop;
    if (scalar @_ == 0) {
        return @{$q};
    } else {
        push @{$q}, pop;
        rev(@_,$q);
    }
}

print join(",",rev((1,2,3,10,1000),[]))."\n";