use strict;
print "Enter characters to permutate : ";
$_ = <STDIN>; s/\s+//g; split(//);
my ($last, $chars);
foreach (sort @_) {
if ($_ ne $last) { $chars .= $_; $last = $_; }
}
for ($_ = length($chars); $_; $_--) {
permutate($_, $chars);
}
sub permutate {
my ($depth, $chars, $pre) = @_;
if ($depth == 1) {
print $pre.substr($chars,$_,1)."\n" for (0..(length($chars)-1)
+);
}
else {
for (0..(length($chars)-$depth)) {
permutate($depth-1, substr($chars,$_+1), $pre.substr($char
+s,$_,1));
}
}
}
This takes input from STDIN rather than ARGV, but does print all the permutations correctly. It's a recursive solution using strings to track permutations.
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