#!/usr/bin/perl
use strict;    
use warnings;  
               
my %h = (      
    a=>{ a=>1, b=>2, c=>3, d=>4 }, 
    b=>{ h=>5, i=>6, j=>5 },  
    c=>{ r=>5, s=>5, t=>5 },  
    e=>{ r=>5, s=>5, t=>4 },                                                                                          
);   
               
for my $k (sort keys %h) {
    my @t = kv_for_largest_v($h{$k});
    print "Key $k: $t[0], $t[1]\n";
}    
               
sub kv_for_largest_v {
    my $hr = shift;
    return undef unless keys %$hr;
    my ($k,$v) = each %$hr;
    while (my ($k2,$v2) = each %$hr) {
        ($k,$v) = ($k2,$v2) if $v2>$v;
    }   
    return $k,$v;
}    

##</code><code>##

    my ($maxkey, $maxmax) = kv_for_largest_v($distances{$key1};

##</code><code>##

sub kv_for_largest_v {
    my $hr = shift;
    return undef unless keys %$hr;
    my ($k,$v) = each %$hr;
    my @rv = ([ $k, $v ]);
    while (my ($k2,$v2) = each %$hr) {
        if ($v2 > $rv->[0][1]) {
            # New maximum value, reset the list
            $rv =  ([ $k2, $v2 ]);
        }
        elsif ($v2 == $rv->[0][1]) {
            # Another copy of the max distance, add to the list
            push @rv, [ $k2, $v2 ];
        }
    }
    return \@rv;
}