order of characters of the string in perl - string

Question

I want to write a code that regards strings with characters in different order as equal as long as same characters are placed in the strings. For example, suppose $a = "ksv", whenever somebody input string value "svk" or "kvs", I want to write a code that these strings are equivalent to $a. Here is an example,
#ans=("ksv", "kvs", "svk", "vsk",......);
if (#input[1] ~~ #ans) {
return 'EXACT_ANS';
}
#input[1] is what user will put the string. At first, I listed all of the different types of order as an array (just like the example) so that if one of elements in the array matches with #input[1], then I return it as a correct answer. However, this is quite a long and tedious work if I have a string with much longer length. Please give me any advice on this. Thank you^^

Answer 1

You want something of the form
if (normalize_string($input) eq normalize_string('ksv')) {
...
}
where normalize_string is a sub that returns the same string for all equivalent inputs, and returns different strings for inputs that aren't equivalent.
The exact definition of normalize_string will vary based on what you consider equivalent.
If you want to ignore duplicate characters (abbc is equivalent to abc):
sub normalize_string {
my %h;
++$h{$_} for split //, $_[0];
return join '', sort keys %h;
}
If the number of instances of each character is pertinent (abbc isn't equivalent to abc):
sub normalize_string {
return join '', sort split //, $_[0];
}
Of course, you can inline the normalized form when the parameter is a constant.
if (normalize_string($input) eq 'ksv') {
...
}