RosettaCodeData/Task/Knapsack-problem-Bounded/Perl-6/knapsack-problem-bounded-2.pl6

56 lines
1.6 KiB
Raku

my $raw = qq:to/TABLE/;
map 9 150 1
compass 13 35 1
water 153 200 2
sandwich 50 60 2
glucose 15 60 2
tin 68 45 3
banana 27 60 3
apple 39 40 3
cheese 23 30 1
beer 52 10 1
suntancream 11 70 1
camera 32 30 1
T-shirt 24 15 2
trousers 48 10 2
umbrella 73 40 1
w_trousers 42 70 1
w_overcoat 43 75 1
note-case 22 80 1
sunglasses 7 20 1
towel 18 12 2
socks 4 50 1
book 30 10 2
TABLE
my @items;
for split(["\n", /\s+/], $raw, :skip-empty) -> $n,$w,$v,$q {
@items.push: %{ name => $n, weight => $w, value => $v, quant => $q}
}
my $max_weight = 400;
sub pick ($weight, $pos) {
state %cache;
return 0, 0 if $pos < 0 or $weight <= 0;
my $key = $weight ~ $pos;
%cache{$key} or do {
my %item = @items[$pos];
my ($bv, $bi, $bw, @bp) = (0, 0, 0);
for 0 .. %item{'quant'} -> $i {
last if $i * %item{'weight'} > $weight;
my ($v, $w, @p) = pick($weight - $i * %item{'weight'}, $pos - 1);
next if ($v += $i * %item{'value'}) <= $bv;
($bv, $bi, $bw, @bp) = ($v, $i, $w, |@p);
}
%cache{$key} = $bv, $bw + $bi * %item{'weight'}, |@bp, $bi;
}
}
my ($v, $w, @p) = pick($max_weight, @items.end);
{ say "{@p[$_]} of @items[$_]{'name'}" if @p[$_] } for 0 .. @p.end;
say "Value: $v Weight: $w";