#!/usr/bin/perl
use strict;
use warnings;

my %data = map { chomp; $_ => [ split ] } <DATA>;
my $last = 0;
for ( keys %data ) {
    $last = @{$data{$_}} if @{$data{$_}} > $last;
    $_ = ucfirst lc $_ for @{$data{$_}};
}

for my $index ( 0 .. $last ) {
    for my $name ( map { $data{$_} } keys %data ) {
        next if ! $name->[$index];
        for my $length ( 1 .. length $name->[$index] ) {
            if ( ! Match( $name, $index, $length ) ) {
                $name->[$index] = substr( $name->[$index], 0, $length 
+) ;
                last;
            }
        }
    }
}

sub Short {
    my ( $name, $index, $length ) = @_;
    return join " ",
        @{$name}[ grep $_ < $index, 0 .. $#$name ],
        substr( $name->[$index], 0, $length ),
        @{$name}[ grep $_ > $index, 0 .. $#$name];
}

sub Match {
    my ( $name, $index, $length ) = @_;
    my $s_name = Short( $name, $index, $length );
    for my $t_name ( map { $data{$_} } keys %data ) {
        next if @$name != @$t_name || $name eq $t_name;
        my $s_test = Short( $t_name, $index, $length );
        return 1 if $s_name eq $s_test;
    }
    return 0;
}
print "@{ $data{$_} } => $_\n" for sort keys %data;
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index($t_name->[$index], substr($name->[$index], 0, 1))
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