#! perl -slw
use strict;

sub weightedSum {
    my( $r, $weight ) = ( @_, 1 );
    my $sum = 0;
    for ( @$r ) {
        if( ref ) {
            $sum += weightedSum( $_, $weight + 1 );
        }
        else {
            $sum += $_ * $weight;
        }
    }
    return $sum;
}

my $arrref = [
    [1,1,1,1],
    [1,1, [2,2] ],
    [1, [2, [3,3] ] ]
];

print weightedSum( $arrref );