Knapsack problem/Continuous: Difference between revisions

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{"sausage", 5.9, 98.0}];

// ~~reverse~~ sorted by Value per amount

// Reverse sorted by Value per amount.

const items = raw.sort!q{a.valuePerKG > b.valuePerKG}().release();

const items = raw.sort!q{a.valuePerKG > b.valuePerKG}.release;

~~const~~(Item)[] chosen;

immutable(Item)[] chosen;

real space = 15.0;

foreach (item; items)

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writefln("%10s %7s %7s %7s", "ITEM", "AMOUNT", "VALUE", "$/unit");

writefln("%(%s\n%)", chosen);

~~writeln(~~Item("TOTAL", sum!"amount"~~(chosen)~~, sum!"value"~~(chosen))~~);

Item("TOTAL", chosen.sum!"amount", chosen.sum!"value").writeln;

}</lang>

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welt 3.50 63.38 18.11

TOTAL 15.00 349.38 23.29</pre>

===Alternative Version===

<lang d>~~import~~ ~~std.stdio,~~ ~~std.algorithm;~~

<lang d>void main() {

import std.stdio, std.algorithm;

void main() {

static struct T { string item; double weight, price; }

auto items = [T("beef", 3.8, 36.0),

T("pork", 5.4, 43.0),

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T("welt", 3.7, 67.0),

T("salami", 3.0, 95.0),

T("sausage", 5.9, 98.0)];

T("sausage", 5.9, 98.0)]

~~sort~~!q{a.price/a.weight ~~> b.price/b.weight~~}~~(items)~~;

.schwartzSort!q{ -a.price / a.weight };

auto left = 15.0;

foreach (it; items) {

foreach (it; items)

if (it.weight <= left) {

writeln("Take all the ", it.item);

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return;

left -= it.weight;

} else {

} else

writefln("Take %.1fkg %s", left, it.item);

return writefln("Take %.1fkg %s", left, it.item);

return;

}

}</lang>