my @b = map { $_->[1] }
            sort { $b->[0] <=> $a->[0] }
            map { [ $a[ $_ ]->{total}, $_ ] } 0..$#a;

##</code><code>##

$a[0]->{total} = 0;
$a[1]->{total} = 10;
$a[2]->{total} = 50;
$a[3]->{total} = 40;
$a[4]->{total} = 30;
$a[5]->{total} = 20;

@b = map { $_->[1] } 
     sort { $b->[0] <=> $a->[0] }
     map { [ $a[$_]->{total}, $_ ] } 1..$#a;

print "$b[$_] = $a[$b[$_]]->{total}\n" for 0..$#b;