♻️ refactor(knapsackUnboundedGreedy): Extract reusable code.

Author: make-github-pseudonymous-again

src/Item.js

@@ -0,0 +1,7 @@
+import assert from 'assert';
+
+export default function Item(weight, value) {
+	assert(weight > 0);
+	this.w = weight;
+	this.v = value;
+}

src/index.js

@@ -1,25 +1,31 @@
+import Item from './Item';
 import integerValuesKnapsack from './integerValuesKnapsack';
 import integerValuesKnapsackUnbounded from './integerValuesKnapsackUnbounded';
 import integerWeightsKnapsack from './integerWeightsKnapsack';
 import integerWeightsKnapsackUnbounded from './integerWeightsKnapsackUnbounded';
 import knapsackApprox from './knapsackApprox';
 import knapsackUnboundedGreedy from './knapsackUnboundedGreedy';
+import orderedByDecreasingUtility from './orderedByDecreasingUtility';
 
 /* eslint import/no-anonymous-default-export: [2, {"allowObject": true}] */
 export default {
+	Item,
 	integerValuesKnapsack,
 	integerValuesKnapsackUnbounded,
 	integerWeightsKnapsack,
 	integerWeightsKnapsackUnbounded,
 	knapsackApprox,
 	knapsackUnboundedGreedy,
+	orderedByDecreasingUtility,
 };
 
 export {
+	Item,
 	integerValuesKnapsack,
 	integerValuesKnapsackUnbounded,
 	integerWeightsKnapsack,
 	integerWeightsKnapsackUnbounded,
 	knapsackApprox,
 	knapsackUnboundedGreedy,
+	orderedByDecreasingUtility,
 };

src/knapsackUnboundedGreedy.js

@@ -1,7 +1,9 @@
 import assert from 'assert';
-import {fn, decreasing} from '@aureooms/js-compare';
 import {map, range, sorted} from '@aureooms/js-itertools';
 
+import Item from './Item';
+import orderedByDecreasingUtility from './orderedByDecreasingUtility';
+
 /**
  * 1/2-approximation to the unbounded knapsack problem.
  * Runs in O(n log n) time.
@@ -35,13 +37,4 @@ const subroutine = (W, items) => {
 	return value;
 };
 
-function Item(weight, value) {
-	assert(weight > 0);
-	this.w = weight;
-	this.v = value;
-}
-
-const utility = (x) => x.v / x.w;
-const orderedByDecreasingUtility = fn(decreasing, utility);
-
 export default knapsackUnboundedGreedy;

src/orderedByDecreasingUtility.js

@@ -0,0 +1,6 @@
+import {fn, decreasing} from '@aureooms/js-compare';
+
+const utility = (x) => x.v / x.w;
+const orderedByDecreasingUtility = fn(decreasing, utility);
+
+export default orderedByDecreasingUtility;